Eukaryotes. Slide 1 / 143. Slide 2 / 143. Slide 3 / 143. January 2014

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1 Slide 1 / 143 Slide 2 / 143 Eukaryotes January Vocabulary lick on each word below to go to the definition. 5' cap exocytosis adhering junction exon alternative splicing extracellular matrix cell junction food vacuole central vacuole fungi chitin gap junction chloroplast glycoprotein chromatin golgi appartus chromatin modifying enzyme histone contractile vacuole hydrolytic enzyme cytoskeleton intermediate filament endocytosis intermembrane space endomembrane system intron endosymbiosis lumen eukaryote lysosome Slide 3 / 143

2 Vocabulary lick on each word below to go to the definition. matrix poly- tail microfilament pre-mrn microtubule protist mitochondrion receptor-mediated endocytosis mrn processing RN splicing nuclear envelope rough endoplasmic reticulum nuclear pore smooth endoplasmic reticulum nucleolus stroma nucleosome tight junction nucleus transcription factor organelle transport vesicle peroxisome turgor pressure phagocytosis pinocytosis plasmodesmata Slide 4 / 143 Eukaryotes Unit Topics Slide 5 / 143 The Eukaryotic ell The Nucleus & Gene Expression The Endomembrane System Energy-onverting Organelles Other Organelles & ell Structures lick on the topic to go to that section Slide 6 / 143 The Eukaryotic ell Return to Table of ontents

3 ll ells Slide 7 / 143 ll cells have 4 things in common. They are surrounded by a plasma membrane (or cell membrane). They contain a semifluid substance called the cytosol/cytoplasm. They contain structures called chromosomes, which carry the cell's genes. They have ribosomes, which assemble amino acids into proteins. Eukaryotes vs. Prokaryotes Slide 8 / 143 There are 3 key differences between prokaryotic and eukaryotic cells. Eukaryotic cells are usually larger than prokaryotic cells. Eukaryotic cells have small compartments inside them call organelles. Most eukaryotes (but not all) are multi-cellular organisms. 1Which is NOT a basic feature of all cells? Slide 9 / 143 ll cells are surrounded by a plasma membrane. l cells contain a semifluid substance called the cytoplasm. ll cells contain structures called chromosomes, which are contained the nucleus. ll cells have ribosomes.

4 ell Size Eukaryotic cells are, on average, much larger than prokaryotic cells. The average diameter of most prokaryotic cells is between 1 and 10µm. y contrast, most eukaryotic cells are between 5 to 100µm in diameter. Slide 10 / 143 nimal ell (Eukaryote) acterium (Prokaryote) Surface rea to Volume Ratio Slide 11 / 143 t the time when prokaryotic cells were evolving, there were most likely different sizes of cells. cell's efficiency and ability to survive depended on its surface area to volume ratio. The volume of the cell determines the amount of chemical activity it can carry out per unit time. The surface area of the cell determines the amount of substances the cell can take in from the environment and the amount of waste it can release. s a cell grows in size, it's surface area to volume ratio decreases. It performs chemical reactions faster, but it has a harder time getting nutrients in and waste out. Limits of ell Size Slide 12 / 143 We know that cells need to be small enough so that they have an increased surface area to volume ratio, but be large enough to perform the chemical reactions of metabolism. Most Efficient Least Efficient The smaller the cell, the larger its surface area and the smaller its volume. The bigger the cell, the smaller the surface area is compared to its large volume inside.

5 Organelles Slide 13 / 143 To increase efficiency in the larger cell, eukaryotes evolved many bacterium-sized parts known as organelles. Organelles subdivide the cell into specialized compartments. They play many important roles in the cell. Some transport waste to the cell membrane. Others keep the molecules required for specific chemical reactions located within a certain compartment so they do not need to diffuse long distances to be useful. Organelles Slide 14 / 143 Organelles making up Eukaryotic cells include: Nucleus Lysosomes Ribosomes Peroxisomes Mitochondria Vacuoles Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum hloroplasts Golgi pparatus Multicellular Organisms Slide 15 / 143 Even with organelles, the size of the cell is limited to about 1000µm 3. This is why large organisms must consist of many smaller cells.

6 iversity of Eukaryotes Slide 16 / 143 Protists: The first eukaryotic cells. Protists are single-celled eukaryotes. They range from protozoans to algae. Fungi: These organisms evolved second in time along with plants. Examples include mushrooms, molds, and mildews. Plants: Plants vary in type from the first plants called mosses to the modern flowering plants. nimals : nimals were the last eukaryotes to evolve. nimals range from ancient sponges and hydra to primates. 2Which of the following are prokaryotic cells? Slide 17 / 143 Plants Fungi acteria nimals 3 How did eukaryotes solve the problem of small surface area to volume ratio? Slide 18 / 143 by remaining the same size as prokaryotes by becoming multicellular organisms by compartmentalizing functions into organelles they haven't solved the problem

7 4 ll eukaryotes are multi-cellular. Slide 19 / 143 True False Slide 20 / 143 The Nucleus & Gene Expression Return to Table of ontents The Nucleus Slide 21 / 143 The defining organelle in eukaryotic cell is the nucleus. The nucleus of the cell contains the N and controls the cell's activities by directing protein synthesis from N. prokaryotes: pro: before karyon: kernel/seed (nucleus) eukaryote: eu: true karyon: kernel/seed (nucleus) So prokaryote = "before a nucleus" nd eukaryote = "true nucleus"

8 The iological Nucleus Slide 22 / 143 The nucleus from chemistry with protons and neutrons is not the same nucleus involved with cells. iological Nucleus The biological nucleus is usually, but not always, in the center of a cell and it is sometimes referred to as the "control center" of the cell. Inside the Nucleus Slide 23 / 143 The nucleus is enclosed by a double cell membrane structure called the nuclear envelope. The nuclear envelope has many openings called nuclear pores. Nuclear pores help the nucleus "communicate" with other parts of the cell. Inside the nucleus is a dense region known as the nucleolus. The nucleolus is where rrn is made and ribosomes are assembled. They then exit through the nuclear pores. 3 Main Functions of the Nucleus Slide 24 / To keep and contain a safe copy of all chromosomes (N) and pass them on to daughter cells in cell division. 2. To assemble ribosomes (specifically in the nucleolus). 3. To copy N instructions into RN (via transcription).

9 5ells that contain a "true nucleus" and other membrane bound organelles are. Slide 25 / 143 archaea. bacteria. eukaryotes. prokaryotes. 6 Where is the N of a eukaryote found? Slide 26 / 143 Nucleus Nucleolus Nucleoid Mitochondria 7 How does the nucleus control the activities of the cell? Slide 27 / 143 y making N. y directing protein synthesis. y allowing N to leave the nucleus to make proteins. y sending instructions to the mitochondria.

10 Many ells = Same N Slide 28 / 143 ll cells in a multicellular eukaryote contain the same genome. Every cell has all the genes necessary to make all parts of the organism. ells become specialized by only expressing (turning on) certain genes, a small fraction of all the genes in the genome. These muscle cells and brain cells (neurons) have the same N but they are expressing different genes, that is why their structure and function are so different. Transcription and Translation Slide 29 / 143 Transcription Transcription and translation occur in Eukaryotes the same as in Prokaryotes, but there are extra steps that help regulate expression. Gene Expression in Prokaryotes Slide 30 / 143 Gene expression is regulated using operons that turn genes on and off depending on the chemical environment of the cell.

11 Gene Expression in Eukaryotes Overview Slide 31 / 143 Eukaryotes have much more complex chromosomes that require multiple levels of regulation including: "unpacking" of genes transcription factors RN processing 8 particular triplet of bases in the template strand of N is GT. The corresponding codon for the mrn transcribed is Slide 32 / 143 E GT. UG. T. U. U 9 codon Slide 33 / 143 E consists of two nucleotides. may code for the same amino acid as another codon. consists of discrete amino acid regions. catalyzes RN synthesis. is found in all eukaryotes, but not in prokaryotes.

12 10If the triplet codes for the amino acid proline in bacteria, then in plants should code for Slide 34 / 143 E leucine. valine. cystine. phenylalanine. proline. hromosomes Slide 35 / 143 N is configured into structures called chromosomes. Recall that prokaryotes have one chromosome that is double-stranded and circular. The number of chromosomes a eukaryote has depends on the species. These chromosomes are made up of a complex of tightly coiled N and associated proteins called chromatin. Species hromosome # dders-tongue (a fern) 1440 og 78 Human 46 Rat 42 Pig 38 at 38 Rice 24 Slime Mold 12 Jack Jumper nt 2* *2 for females, 1 for males Source: Wikipedia.com hromatin Slide 36 / 143 The N is tightly wound around proteins called histones, like thread wrapped on a spool. The combination of eight histones and N is called a nucleosome. Video on how N is packaged

13 hromatin's Role in Gene Expression Slide 37 / 143 When N is packed in chromatin it is not accessible to RN polymerase so transcription can not happen. The main factor in the specialization of cells in multi-cellular organisms is what genes are "unpacked" from the chromatin to be exposed to RN polymerase. ll gene sequences are exposed to RN polymerase Some genes exposed No genes exposed hromatin Modifying Enzymes Slide 38 / 143 The genes that need to be expressed are unwound from histones by chromatin modifying enzymes in order to expose their nucleotide sequences. Genes that are unnecessary to a particular cell will remain packed while the neccessary ones are unpacked. 11 No two cells in the human body have exactly the same N. Slide 39 / 143 True False

14 12 How many spools of N and proteins make a nucleosome? Slide 40 / 143 Transcription Slide 41 / 143 Transcription of N into RN occurs in the nucleus of the eukaryotic cell Eukaryotic RN polymerase needs the assistance of proteins called transcription factors to help regulate when a gene is expressed. If all the necessary transcription factors are present for a specific gene, then the gene can be expressed. If any are missing, transcription will not start. There can be thousands of transcription factors in an organism's cells (3,000 in humans). The kind and number of them present in the nucleus at any given time dictate what genes are expressed. Transcription Factors Slide 42 / 143 Transcription factors are proteins that are capable of binding with N. When they bind to areas near the promoter region of the gene they work with RN polymerase to begin the transcription of that gene. They are produced in response to cues from the external environment of the cell. These proteins make the cell capable of turning on genes in response to external stimulus. This is essential to multicellular eukaryotes because it allows the different cells of the organism to communicate and respond to situations in unison. Video on regulated transcription

15 External Signals Slide 43 / 143 External signal activates membrane bound protein (receptor) Signal Receptor Metabolic pathway that produces a specific transcription factor in response to signal. The product enters the nucleus. Nucleus Transcription Factor ell 13 The first step in eukaryotic gene expression is... Slide 44 / 143 transcription translation RN processing unraveling the gene 14 Where does transcription occur in eukaryotic cells? Slide 45 / 143 nucleus nucleiod cytoplasm cell membrane

16 15 Once the N is unwound from the chromatin, which of the following is necessary to begin transcription? Slide 46 / 143 RN polymerase ribosome transcription factors both & 16 Transcribe the following eukaryotic gene sequence: TGTTTGGGT Slide 47 / 143 TGTTTGGGT TTTTG UUGUUG UUUGUUUGGGU mrn Processing Slide 48 / 143 fter Transcription, the transcript is known as pre-mrn. Enzymes in the nucleus modify pre-mrn before the genetic messages are sent to the cytoplasm. This is know mrn processing. uring mrn processing, both ends of the pre-mrn are altered. Some interior sequences of pre-mrn may be cut out, and other parts spliced together.

17 lteration of mrn Ends Slide 49 / 143 The 5`end of the pre-mrn receives a molecule known as a nucleotide (or 5') cap. This cap is a modified guanine molecule (the G in, T,, G) pre-mrn 5' cap added UGUUG GUGUUG lteration of mrn Ends Slide 50 / 143 The 3` end of the pre-mrn gets a poly- tail. This tail is series of adenosine () nucleotides. original pre-mrn UGUUG 3' tail added GUGUUG lteration of mrn Ends Slide 51 / 143 The modifications to the ends of the pre-mrn have several functions: They facilitate the export of mrn from the nucleus to the cytoplasm. They protect mrn from hydrolytic enzymes once it is in the cytoplasm. They help ribosomes attach to the mrn so they can be translated into a protein.

18 RN Splicing Slide 52 / 143 Most eukaryotic genes and their RN transcripts have long noncoding stretches of nucleotides that lie between coding regions. These noncoding regions are called intervening sequences, or introns. The other regions called exons (because they are eventually expressed), are usually translated into amino acid sequences. RN splicing removes introns and joins exons, creating an mrn molecule with a continuous coding sequence. 17What are the coding segments of a stretch of eukaryotic N called? Slide 53 / 143 introns exons codons replicons mrn Processing Slide 54 / 143 This is an example of a pre-mrn becoming a final transcript.

19 Slide 55 / 143 lternative RN Splicing Some genes can code more than one kind of polypeptide, depending on which segments are treated as exons during RN splicing. lternative splicing allows the number of different proteins an organism can produce to be much greater than its number of genes. lternative RN Splicing Slide 56 / 143 N sequence TTTGGGTTTGGG Pre-mRN (ap)-uuuggguuuggg-(tail) lternate splices (ap)-uuu UUU -(Tail) OR (ap)-gg G GG-(Tail) Resulting polypeptide (protein) Phe - Lys - Phe - Lys OR Gly - Pro - Gly lternate splicing can dramatically change the length and/or the sequence of the polypeptide chain that will be made 18Which of the following helps to stabilize mrn by inhibiting its degradation? Slide 57 / 143 E RN polymerase ribosomes 5' cap poly- tail both and

20 19 transcription unit that is 8,000 nucleotides long may use 1,200 nucleotides to make a protein consisting of 400 amino acids. This is best explained by the fact that Slide 58 / 143 many noncoding nucleotides are present in mrn. there is redundancy and ambiguity in the genetic code. many nucleotides are needed to code for each amino acid. nucleotides break off and are lost during the transcription process. 20Once transcribed, eukaryotic pre-mrn typically undergoes substantial alteration that includes Slide 59 / 143 E removal of introns. fusion into circular forms known as plasmids. linkage to histone molecules. union with ribosomes. fusion with other newly transcribed mrn. 21 mutation in which of the following parts of a gene is likely to be most damaging to a cell? Slide 60 / 143 intron exon would be equally damaging.

21 22lternative RN splicing Slide 61 / 143 can allow the production of proteins of dramatically different sizes from a single mrn. can allow the production of proteins of dramatically different amino acid sequences from a single mrn. oth can happen Entrance into the ytoplasm Slide 62 / 143 fter the finalized mrn transcript is complete and correct, the pores in the nuclear envelope allow it to pass to the cytoplasm where it can be translated into proteins by ribosomes. The nuclear pore is a protein structure that controls the traffic flow of the nucleus. Each nuclear pore is made up of hundreds of individual proteins that insure only mrns with proper caps and tails can make it to the cytoplasm. egradation of mrn Slide 63 / 143 Hydrolytic enzymes in the cytoplasm breakdown mrn molecules. The length of time an mrn suvives in the cytoplasm relates to how much protein is made from it. Longer time in the cytoplasm means more translation by ribosomes. The length of the poly- tail is one of many factors that determines the time of survival in the cytoplasm. The longer the tail, the longer it's survival.

22 23 What is the importance of nuclear pores? Slide 64 / 143 They allow the nucleus to communicate with other parts of the cell. They allow N to leave the nucleus in order to direct protein synthesis. They allow RN to leave the nucleus in order to be translated in the cytoplasm. They allow single stranded N molecules to enter the nucleus and assemble into the double helix. Summary of Gene Expression Regulation in Eukaryotes Slide 65 / 143 The gene must be unpacked from chromatin The right transcription factors must be present Transcription occurs ap and tail must be added to the mrn Pre-mRN must be edited (spliced) Nuclear pores allow passage to the cytoplasm mrn comes into contact with a ribosome Translation occurs Protein is used within the cell or exported to the environment Slide 66 / 143 Endomembrane System Return to Table of ontents

23 The Endomembrane System Slide 67 / 143 Several organelles, some made up mainly of membranes, form a type of assembly line in the cell. They make a protein, then process and ship it to its final destination whether that be inside or outside the cell. Organelles included in this system include the nucleus, rough and smooth endoplasmic reticulum, golgi appartus, and lysosomes. ollectively, we refer to them as the endomembrane system. Note: The plasma membrane is also considered part of this system The Endomembrane System Slide 68 / 143 Endoplasmic Reticulum Slide 69 / 143 When RN leaves the nucleus, it enters the endoplasmic reticulum (ER). This organelle is a series of membrane-bound sacs and tubules. It is continuous with the outer membrane of the nuclear envelope (reticulum comes from the latin word for little net). There are two types of endoplasmic reticulum: rough and smooth.

24 Rough Endoplasmic Reticulum Slide 70 / 143 Rough ER has ribosomes attached to its membrane (thus a rough appearance). These ribosomes synthesize proteins that will be used in the plasma membrane, secreted outside the cell or shipped to another organelle called a lysosome. s proteins are made by the ribosomes, they enter the lumen (opening) of the ER where they are folded and processed. Ribosomes Slide 71 / 143 Recall that the ribosome is made of rrn and proteins. This is where translation occurs. Ribosomes consist of two subunits, a small and a large. Each subunit consists of proteins and rrn. The two subunits come together when proteins need to be made. Small subunit Large subunit Ribosomes Slide 72 / 143 Recall ribosomes make peptide bonds between amino acids in translation. The instructions for making ribosomes are in the N. From N, rrn is made. Some of the rrn is structural and other rrn holds the code from the N to make the ribosomal proteins from mrn. transcription translation N mrn Protein

25 24 Where are ribosomal subunits made in the cell? Slide 73 / 143 ytoplasm Nucleus Nucleolus On the Plasma membrane 25 What do ribosomes consist of? Slide 74 / 143 proteins and N proteins and rrn proteins only N only 26 List all the parts of the endomembrane system. Slide 75 / 143 rough and smooth endoplasmic reticulum, golgi appartus, lysosomes nucleus, rough and smooth endoplasmic reticulum, golgi appartus, lysosomes nucleus, rough and smooth endoplasmic reticulum, golgi appartus nucleus, rough and smooth endoplasmic reticulum, golgi appartus, lysosomes, plasma membrane

26 27 Which of the following is involved in making proteins? Smooth E.R. Slide 76 / 143 Ribosomes N Nuclear membrane Smooth Endoplasmic Reticulum Slide 77 / 143 This type of ER is called Smooth because it lacks ribosomes on its surface. (it looks smooth compared to rough ER) There are a variety of functions of this organelle, which include: making lipids. processing certain drugs and poisons absorbed by the cell. storing calcium ions (for example, in muscle cells). Note: The liver is an organ that detoxifies substances that are brought into the body. Therefore, liver cells have huge amounts of Smooth ER. Protein Transport Slide 78 / 143 Once the proteins are processed, short chains of sugars are sometimes linked to these proteins, which are then known as glycoproteins. These glycoproteins serve as "zip codes" that will tell the protein where it will go. When the molecule is ready to be exported out of the ER, it gets packaged into a transport vesicle. This vesicle is made of membranes from the ER itself. The transport vesicle travels to another organelle known as the Golgi apparatus.

27 28 The endomembrane system serves to Slide 79 / 143 ship cell products to places in and out of the cell assemble N give directions to other organelles create pathways for organelles to travel 29 What determines if we classify endoplasmic reticulum as smooth or rough? Slide 80 / 143 presence or absence of nuclear pores presence or absence of genetic material presence or absence of ribosomes presence of absence of N 30 Where in the cell are lipids made? Slide 81 / 143 Nucleus Ribosomes Rough endoplasmic reticulum Smooth endoplasmic reticulum

28 Golgi pparatus Slide 82 / 143 The main function of this organelle is to finish, sort, and ship cell products. It works like the postal department of the cell. Structurally, the golgi consists of stacked flattened sacs (sort of looks like a stack of pita bread). Golgi pparatus Slide 83 / 143 The Golgi is located near the cell membrane. The Golgi works closely with the ER of a cell. It receives and modifies substances manufactured by the ER. Once the substances are modified, they are shipped out to other areas of the cell. One key difference between the Golgi apparatus and endoplasmic reticulum is that the sacs comprising the Golgi are not interconnected. The Golgi pparatus & the ER Slide 84 / 143 The Golgi receives transport vesicles that bud off from the ER and contain proteins. It takes the substances contained in these vesicles and modifies them chemically in order to mark them and sort them into different batches depending on their destination. The finished products are then packaged into new transport vesicles which will then move to lysosomes, or will be inserted into the plasma membrane or dumped out of the cell if the protein is a secretory protein. Video on Protein Trafficking through the Golgi

29 31 difference between the Golgi pparatus and the ER is that Slide 85 / 143 The ER takes the vesicles from the Golgi to transport The sacs making the Golgi are not interconnected The Golgi has ribosomes, the ER does not There is no difference, they are part of the same organelle 32 Which organelle receives and modifies substances from the endoplasmic reticulum? Slide 86 / 143 Nucleus Ribosomes Lysosomes Golgi odies Lysosomes Slide 87 / 143 Some proteins from the Golgi pparatus are transported to the lysosomes. s the name suggests, a lysosome is an organelle that breaks down other substances. (lyse: to cause destruction) They consist of hydrolytic enzymes enclosed within a membrane. Hydrolytic enzymes break polymers into monomers through hydrolysis.

30 Lysosomes Slide 88 / 143 Lysosomes may fuse with food-containing organelles called vacuoles and then the enzymes digest the food, releasing nutrients into the cell. Protists do this. amaged or unneeded proteins may become enclosed within a membranous vesicle which then fuses with a lysosome. The organic molecules from the breakdown process are recycled and reused by the cell. Peroxisomes Slide 89 / 143 peroxisome is a specific type of lysosome that forms and breaks down hydrogen peroxide (H2O2) which is toxic to cells. In all cells, hydrogen peroxide forms constantly (from the combining of hydrogen and oxygen as bi-products of metabolism) and needs to be broken down quickly. Important note: Peroxisomes are not part of the endomembrane system. 33 Which organelle contains hydrolytic enzymes that break down other substances? Slide 90 / 143 Endoplasmic Reticulum Golgi odies Lysosomes Vacuoles

31 34 Which is not a function of lysosomes? Slide 91 / 143 aiding the cell in creating ribosomes fusing with vacuoles to digest food breaking polymers into monomers recycling worn out cell parts Plasma Membrane Remember the plasma membrane is a phospholipid bilayer with proteins and other molecules interspersed throughout. Slide 92 / 143 Some proteins from the Golgi pparatus become embedded in the membrane. Others are transported through the membrane to the external environment. Plasma Membrane Slide 93 / 143 The 3 main functions of the plasma membrane: Selective Permeability Protection Structural support

32 Membrane Transport - Review Passive transport is the movement of substances from an area of high concentration to an area of low concentration without the requirement an energy input. Types include diffusion, osmosis, and facilitated diffusion. Passive Transport ctive Transport (REQUIRES ENERGY) Slide 94 / 143 ctive transport is the movement of substances from an area of low concentration to an area of high concentration and requires an input of energy. 35 Which of the following statements about the role of phospholipids in forming membranes is correct? Slide 95 / 143 they are completely insoluble in water they form a single sheet in water they form a structure in which the hydrophobic portion faces outward they form a selectively permeable structure 36 ctive transport moves molecules Slide 96 / 143 with their concentration gradients without the use of energy with their concentration gradients using energy against their concentration gradients without the use of energy against their concentration gradients using energy

33 37 Which of the following processes includes all others? Slide 97 / 143 passive transport facilitated diffusion diffusion of a solute across a membrane osmosis Large Molecules and the Plasma Membrane Slide 98 / 143 Many proteins created by the cell are too large to pass through the membrane, even using protein carrier or integral proteins. How do these macromolecules exit the cell? When the substance needs other ways of getting into or out of a cell, they will enter and exit by fusing with the cell membrane. There are several special functions of the membrane as larger substances enter and exit the cell. To excrete a macromolecule from the cell, the vesicles that enclose the proteins fuse with the plasma membrane and the vesicles then open up and spill their contents outside of the cell. Exocytosis Exocytosis Slide 99 / 143 This process is known as exocytosis. The vesicle will become part of the cell membrane. This is how secretory proteins from the Golgi exit the cell. This is true for insulin in the pancreas.

34 Insulin - Secretory Protein Slide 100 / 143 Insulin is a protein hormone made by certain cells of the pancreas that enable cells to take glucose (sugar) in from the blood. Insulin is a secretory protein made in the rough ER. Specifically, it is secreted out of the pancreas cells into the blood stream. Endocytosis Slide 101 / 143 The opposite of exocytosis is endocytosis. In this process, the cell takes in macromolecules or other particles by forming vesicles or vacuoles from its plasma membrane. This is how many protists ingest food particles 3 Types of Endocytosis Slide 102 / 143

35 3 Types of Endocytosis Slide 103 / 143 Phagocytosis Is for taking in solid particles. ("phago" mean to eat) Pinocytosis Is for taking in liquids. However what the cell wants is not the liquid itself, but the substances that are dissolved in the liquid. ("pino" means to drink) Receptor-mediated endocytosis requires the help of a protein coat and receptor on the membrane to get through. 38 The process by which a cell ingests large solid particles, therefore it is known as "cell eating". Slide 104 / 143 Pinocytosis Phagocytosis Exocytosis Osmoregulation 39 Protein coated vesicles move through the plasma membrane via this process: Slide 105 / 143 Phagocytosis ctive Transport Receptor-Mediated Endocytosis Pinocytosis

36 40 fter a vesicle empties its contents outside a cell, the vesicle becomes part of: Slide 106 / 143 the Golgi the plasma membrane another vesicle the extracellular fluid Slide 107 / 143 Energy-onverting Organelles Return to Table of ontents Energy-onverting Organelles Slide 108 / 143 hloroplasts reside in plant cells and some protists and convert solar radiation into energy stored in the cell for later use. Mitochondria reside in all eukaryotic cells and convert chemical energy from glucose into TP. Interestingly, both chloroplasts and mitochondria have their own N, separate from that found in the nucleus of the cell. They also have a double cell membrane.

37 hloroplasts Slide 109 / 143 These organelles convert solar energy to chemical energy through photosynthesis. hloroplasts are partitioned into three major compartments by internal membranes: Thylakoids Stroma Intermembrane space eukaryotic chloroplast Thylakoids Slide 110 / 143 Remember that during photosynthesis it is on the thylakoid that the Light ependent Reactions take place. eukaryotic chloroplast In prokaryotes, thylakoids are areas of highly folded membranes. In eukaryotes, they are stacked in the chloroplasts. The fluid outside these stacks of thylakoids is called the stroma; this is where the alvin cycle takes place. Mitochondria Slide 111 / 143 Mitochondria are sometimes referred to as the "powerhouses" of the cell. They convert chemical energy (glucose) into a more usable and regenerative form of chemical energy (TP). The mitochondria is also partitioned like the chloroplast. They only have two compartments as opposed to three in the chloroplast. Matrix Intermembrane space

38 Mitochondria and Respiration Slide 112 / 143 Remember cell respiration must take place near a membrane so that a proton gradient can be built in a "membrane space" that is separate from the rest of the cell. Thus, the membrane would separate the inner volume, with a deficit of protons, from the outside, with an excess. In prokaryotes, the "inter-membrane space" is between the cell membrane and the cell wall. In eukaryotes, that membrane is the inter-membrane space of the mitochondria in between the inner membrane and outer membrane. The Evolution of Eukaryotes Slide 113 / 143 The mitochondria and chloroplast are different from other eukaryotic organelles because they have their own N, their own ribosomes, and have a double cell membrane. In 1970, Lynn Margulis published the "Theory of Endosymbiosis" to explain these facts. The theory states that the mitochondria and chloroplast were once free-living prokaryotes that got taken up (or "eaten") by another prokaryote. The mitochondria was a bacteria that could make its own TP. The chloroplast was a bacteria that could perform photosynthesis. endo: within bio: life sym: together sis: condition endosymbiosis = living together, within Endosymbiotic Theory Slide 114 / 143 When they got taken up by another prokaryote, they dragged the one prokaryote's cell membrane around theirs, thus the double cell membrane. This now allowed the "new" eukaryote to make its own TP or be able to do photosynthesis and make its own food. Thus the evolution of eukaryotes. Note: The nucleus and flagella could also have the same possible roots although they are not as heavily supported with evidence as the mitochondria and chloroplast.

39 Evidence for Symbiosis Slide 115 / 143 oth mitochondria and chloroplasts can arise only from preexisting mitochondria and chloroplasts. They cannot be form in a cell that lacks them. oth mitochondria and chloroplasts have their own N and it resembles the N of bacteria not the N found in the nucleus oth mitochondrial and chloroplast genomes consist of a single circular molecule of N, just like in prokaryotes. oth mitochondria and chloroplasts have their own proteinsynthesizing machinery, and it more closely resembles that of bacteria than that found in the cytoplasm of eukaryotes. The Mitochondrial Eve Slide 116 / 143 Since mitochondrial N is not in the cell nucleus, it is only passed along from mother to child; animals, including you, inherit your mitochondria from your mother only. This is because the egg from our mothers contained her organelles. (ad's sperm only contains the chromosomes, none of his organelles usually). ll of our organelles we inherited from our mothers. Mitochondrial N is a way to trace maternal heritage through a family or through a species. The "Mitochondrial Eve" is the first human female that gave rise to all humans. In theory, we can trace all humans back to her through our mitochondrial N. 41 Which organelle converts food energy into chemical energy that the cell can use? Slide 117 / 143 Nucleus hloroplast Mitochondrion Golgi

40 42 Which organelle converts solar energy into chemical energy in plants and other photosynthetic organisms? Slide 118 / 143 Nucleus hloroplast Mitochondrion Golgi 43 Which of the following is not true of mitochondria and chloroplasts? Slide 119 / 143 They are present in all eukaryotic cells They have their own N They have their own ribosomes They are surrounded by a double membrane 44 Which of the following does NOT provide evidence for the endosymbiotic theory? Slide 120 / 143 Mitochondria and chloroplasts both have their own N. Mitochondria and chloroplasts both come from pre-existing mitochondria and chloroplasts. The N of mitochondria and chloroplasts resembles the N found in nuclei. The N of mitochondria and chloroplasts resembles that of bacteria.

41 Slide 121 / 143 Other Organelles and ellular Structures Return to Table of ontents Vacuoles Vacuoles are membranous sacs and they come in different shapes and sizes and have a variety of functions. Slide 122 / 143 entral Vacuole PLNT ELL PROTIST entral Vacuoles Slide 123 / 143 entral Vacuoles in plants store water. bsorbing water makes a plant cell more turgid, or having more pressure inside - leading to strength and rigidity. entral vacuoles that are full will take over most of the cytoplasm and literally push the organelles to the sides of the cell. It can also store vital chemicals, pigments and waste products.

42 Turgor Pressure Slide 124 / 143 Increased turgor pressure results from the central vacuole being full with water. It presses out on the cell membrane which then presses out on the cell wall. The plant cell will not explode or lose its shape like an animal cell would in a hypotonic environment. When the turgor pressure decreases the cell is limp and droopy. This is associated with wilted, limp lettuce, as well as droopy flowers. ontractile Vacuoles Slide 125 / 143 ontractile vacuoles can be found in certain single-celled protists. These act as a pump to expel excess water from the cell. This is especially helpful to those organisms living in a freshwater environment to keep the cell from exploding. Food Vacuoles Slide 126 / 143 Food Vacuoles are mainly found in protists. The protist ingests food particles. The particles then fuse with a lysosome. The lysosome contains hydrolytic enzymes that break the food down. Paramecium fed dyed food showing vacuoles.

43 45 n organelle found in plant cells that stores water as well as other important substances is called the. Slide 127 / 143 Lysosome ontractile Vacuole entral Vacuole Golgi bodies 46 Food vacuoles are primarily found in which organisms? Slide 128 / 143 Plants nimals Protists acteria ytoskeleton Slide 129 / 143 ytoskeleton is a network of fibers within the cytoplasm. Three types of fibers collectively make up the cytoskeleton: Microfilaments Intermediate filaments Microtubules These fibers provide structural support and are also involved in various types of cell movement and motility.

44 47 ells can be described as having a cytoskeleton of internal structures that contribute to the shape, organization, and movement of the cell. ll of the following are part of the cytoskeleton except Slide 130 / 143 the nuclear envelope. microtubules. microfilaments. intermediate filaments. 48 Which of the following is not a known function of the cytoskeleton? Slide 131 / 143 to maintain a critical limit on cell size to provide mechanical support to the cell to maintain the characteristic shape of the cell to hold mitochondria and other organelles in place within the cytosol ell wall The cell wall is an outer layer in addition to the plasma membrane, found in fungi, algae, and plant cells. Slide 132 / 143 The composition of the cell wall varies among species and even between cells in the same individual. ll cell walls have carbohydrate fibers embedded in a stiff matrix of proteins and other carbohydrates. Plant cell walls are made of the polysaccharide cellulose. Fungal cell walls are made of the polysaccharide chitin.

45 Extracellular Matrix Slide 133 / 143 The cells of many multi-cellular animals are surround by a extracellular matrix (EM). The EM provides structural support to the cells in addition to providing various other functions such as anchorage, cellular healing, separating tissues from one another and regulating cellular communication. The EM is primarily composed of an interlocking mesh of proteins and carbohydrates. ell Surfaces and Junctions Slide 134 / 143 ell surfaces protect, support, and join cells. ells interact with their environments and each other via their surfaces. ells need to pass water, nutrients, hormones, and many, many more substances to one another. djacent cells communicate and pass substances to one another through cell junctions. nimal and plant cells have different types of cell junctions. This is mainly because plants have cell walls and animal cells do not. Plant ell Junctions Slide 135 / 143 Plant cells are supported by rigid cell walls made largely of cellulose. They connect by plasmodesmata which are channels that allow them to share water, food, and chemical messages.

46 Slide 136 / 143 nimal ell Junctions Tight junctions dhering junctions ommunicating (Gap) junctions Tight Junctions Slide 137 / 143 Tight junctions can bind cells together into leakproof sheets tight junction Example: the cells of the lining of the stomach or any epithelial lining where leaking of substances is not good. dhering Junctions Slide 138 / 143 dhering junctions fasten cells together into strong sheets. They are somewhat leakproof. Example: actin is held together in muscle.

47 ommunicating (Gap) Junctions Slide 139 / 143 Gap junctions allow substances to flow from cell to cell. They are totally leaky. They are the equivalent of plasmadesmata in plants. Example: important in embryonic development. Nutrients like sugars, amino acids, ions, and other molecules pass through. 49 Which type of junction is found in plant cells? Slide 140 / 143 Gap junction Plasmodesmata Tight junction dhering junction 50 Which type of junction allows for the exchange of materials between animal cells? Slide 141 / 143 Gap junction Plasmodesmata Tight junction dhering junction

48 Plant vs. nimal ell Organelles Slide 142 / 143 lick here to review the similarities and difference between plant and animal cells Organelles in nimal and Plant ells Only Plant oth Only nimal Slide 143 / 143 mitochondria golgi apparatus smooth ER central vacuole cell wall rough ER ribosomes lysosomes plasma nucleus membrane chloroplasts