Cells & Bacteria Notes

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Jasper Boyd
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1 Cells & Bacteria Notes

2 4 Major Macromolecules Macromolecules are large molecules. The four groups of macromolecules are essential to the structure and function of a cell.

3 Group Building Block Large Molecule Function Carbohyd rate Protein Nucleic acid Monosacc haride Amino acid Polysaccharide Polypeptide or protein Nucleotide Polynucleotide or nucleic acid Energy storage, receptors, structure of plant cell wall Enzymes, structure, receptors, transport, and more Information storage and transfer Lipid Glycerol, fatty acids Fats, oils, Membrane waxes, structure, energy phosopholipids, storage, insulation steroids

4 What Are Cells? The cell is the simplest unit of life. From the unicellular bacteria to multicellular animals, the cell is one of the basic organizational principles of biology.

5 Eukaryotic Cells and Prokaryotic Cells There are two primary types of cells: eukaryotic cells and prokaryotic cells. Eukaryotic cells are called so because they have a true nucleus, which houses DNA and is contained within a membrane. Prokaryotic cells do not have a true nucleus. DNA in a prokaryotic cell is not separated from the rest of the cell but coiled up in a region called the nucleoid.

6 Typically, eukaryotic cells are more complex and much larger than prokaryotic cells. On average, prokaryotic cells are about 10 times smaller in diameter than eukaryotic cells.

7 The nucleus Where the DNA is kept and RNA is transcribed. RNA is moved out of the nucleus through the nuclear pores. Proteins needed inside the nucleus are transported in through the nuclear pores. The nucleolus is usually visible as a dark spot in the nucleus, and is the location of ribosome formation.

8 Ribosomes Where RNA is translated into protein. This process is called protein synthesis. Large numbers of ribosomes are found in cells. Ribosomes float freely in the cytoplasm, and are also bound to the endoplasmic reticulum (ER). Very small, made up of proteins and RNA. Ribosomes do not have a membrane.

9 The Endoplasmic Reticulum (ER) The transport system for molecules needed in the cytoplasm. There are two types of ER, rough & smooth. Rough ER has ribosomes attached to it, and smooth ER does not.

10 The Lysosome A small bubble that contains digestive enzymes. It breaks down molecules into their base components.

11 The Cell Membrane Functions as a semipermeable barrier, controls what enters and exits the cell. Composed of a phospholipid bilayer or fluid-mosaic model. The most common molecule in the model is the phospholipid, which has a hydrophilic head and two hydrophobic tails. These phospholipids are aligned tail to tail, forming a hydrophobic region between the hydrophilic heads on the inner and outer surfaces.

12 The Cytoplasm Defined as the liquid material between the cell membrane and the nuclear envelope.

13 Vacuoles Storage areas. Vesicles are much smaller than vacuoles and function in transport within and to the outside of the cell.

14 The Golgi Bodies Change molecules and divide them into small vesicles. These can be sent to various locations in the cell. Golgi are flattened stacks of membrane-bound sacs. They function as a packaging plant, modifying proteins.

15 Mitochondria The main energy source of the cell, often called the "power plants" of the cell. This is where ATP is created. Mitochondria

16 Chloroplasts Have their own DNA (like mitochondria). Found in plant cells, and utilize photosynthesis to make food.

17 Cell Wall A tough, rigid layer that surrounds some types of cells. A characteristic feature to cells of plants, bacteria, fungi & algae. Located outside the cell membrane. Major function is to provide strength, support & protection. Cell wall composition varies from species to species. Mitochondria

19 Bacterial Cell Wall A peptidoglycan cell wall composed of disaccharides and amino acids gives bacteria structural support. The bacterial cell wall is often a target for antibiotic treatment. Two types of cell walls: Gram-Positive & Gram- Negative. Structurally they are slightly different.

20 Bacterial Structure Very small cell. Lack membrane bound organelles. Lack nuclear membrane. DNA circular Nucleoid. Biochemical processes take place in the cytoplasm.

21 Eukaryotic and Prokaryotic Cell Structures Cell Structure Prokaryotic Cell Eukaryotic Cell Cell Membrane Yes Yes Cell Wall Yes No Centrioles No Yes Chromosomes One long DNA strand Many Cilia or Flagella Yes, simple Yes, complex Endoplasmic Reticulum No Golgi Complex No Yes Lysosomes No Common Mitochondria No Yes Nucleus No Yes Peroxisomes No Common Ribosomes Yes Yes Yes (some exceptions)

22 Reproduce through: BINARY FISSION - Asexual Reproduction

Encased by a tough outer covering that resists drying out,

23 Endospores Survival Mechanism. Contains Bacterial DNA and a Small amount of cytoplasm. Encased by a tough outer covering that resists drying out, temperature extremes, harsh chemicals. Bacterium rests and doesn t reproduce. Germinates when conditions are favorable.

24 Importance of Bacteria: Colonize every environment on earth. Over 80% of life s history was bacterial. You have more bacterial cells than human cells. Play a key role in the biosphere. Pathogenic microbes are the most important cause of human disease and death.

26 Monera: Once the Prokaryotic Kingdom, has now been split into 2 new kingdoms: Archaebacteria Eubacteria

28 Archaebacteria: Has three main sub categories: Extreme Thermophiles Methanogens Extreme Halophiles

29 Extreme Thermophiles Found in Hot pots, Hydrothermal vents. They like High temperatures, and Sulfur. Thermus Aquaticus

30 Methanogens Found in Marshes, lake sediments, digestive tracts of mammals (cows), sewage disposal plants, Natural Gas. Like methane.

31 Extreme Halophiles Found in Dead Sea, Great Salt Lake, Evaporating Ponds, Salt, Like high salt concentrations. Halobacterium halobium

32 Eubacteria are Heterotrophs: Use organic molecules as food source. Parasites - Obtain nutrients from living organisms. Saprophytes - Feed on dead organisms and organic wastes. Recyclers or decomposers.

33 Eubacteria are Photosynthetic Autotrophs: Use Sunlight to make food. Cyanobacteria - Blue-green, red or yellow. Chains of independent cells.

34 Eubacteria are Chemosynthetic Autotrophs: Make food from chemosynthesis using Sulfur, Nitrogen Metabolism. Obligate aerobes - Require oxygen. Obligate anaerobes - Killed by oxygen. Facultative Aerobes - Both with or without oxygen (cellular respiration vs. fermentation.)

35 Bacteria are usually classified on the basis of their shapes. Broadly, they can be divided into: Rod-shaped bacteria (Bacilli) Sphere-shaped bacteria (Cocci) Spiral-shaped bacteria (Spirilla)

36 Bacteria Cell Shapes

37 Rod or Bacillus

38 Many bacteria live singly, others are found in aggregates or clusters. These aggregates are named based on the arrangement of the cells of which they are composed. diplo: are in sets of two. strepto: are in chains staphylo: are in clusters (like a bunch of grapes).

found in the colon Entamoeba histolytica: Ent, intestinal;

41 The Meaning of the Names of Some Microorganisms: Escherichia coli: Named after Theodore Escherich in 1888; found in the colon Entamoeba histolytica: Ent, intestinal; amoebae, shape/movement; histo, tissue; lytic, lysing or digesting tissue

42 Strain: A subgroup of a species with one or more characteristics that distinguish it from other members of the same species.

Overview of Cells. Prokaryotes vs Eukaryotes The Cell Organelles The Endosymbiotic Theory

Overview of Cells. Prokaryotes vs Eukaryotes The Cell Organelles The Endosymbiotic Theory Overview of Cells Prokaryotes vs Eukaryotes The Cell Organelles The Endosymbiotic Theory Prokaryotic Cells Archaea Bacteria Come in many different shapes and sizes.5 µm 2 µm, up to 60 µm long Have large