Science TAKS 11 Study Guide Objective 2

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1 Objective 2 Organization of Living Systems - 4B Biology (4) cells structures and functions, and how viruses differ / 4B-cellular processes Key parts of the cell: Cell Membrane - encloses cell and controls what enters and leaves the cell. Cytoplasm - surrounds organelles; transports some materials. Endoplasmic reticulum - transports and stores some substances, throughout the cell. Ribosome - builds proteins; (protein synthesis) Lysosome - breaks down nutrients and foreign substances. Nucleus - control center; regulates metabolic activities, is surrounded by a double-layered membrane. Chromosomes - genetic material (The DNA) with proteins. Chromosomes are usually broken down into chromatin. Nuclear Membrane - encloses nucleus and controls what enters and leaves the nucleus. Nucleolus - contains RNA; sends mrna to ribosome with protein blueprints. Golgi apparatus - secretes and stores secretions for transport out of the cell. Chloroplast - manufactures food in green plants; photosynthesis. Cell wall - protective out barrier of plant cells Centrosomes - aids in mitosis in animal cells. Vacuole - stores food, water, wastes and building materials Mitochondria - powerhouse of cell; cellular respiration. Prokaryotic Cells (bacteria) Eukaryotic Cells (plant & animal) 1. No nuclear membrane (nucleoid region) 1. Definite membrane bound nucleus 2. No membrane bound organelles 2. Contains membrane bound organelles 3. Found only in the kingdoms Eubacteria and Archabacteria 3. Found in Kingdoms: Animal, Plant, Fungi, and Protista 4. Size 0.1 um - 10 um. 4. Size 10 um-100 um. Cell size is governed by several factors: 1. DNA must be available to produce the enzymes and proteins needed for proper functioning. 2. Surface area to volume ratio. As the cell increases in size the volume increased geometrically while the surface area increases arithmetically. 4 Types of Cellular Transport - used to maintain Homeostasis (balance) by moving fluids, waste and nutrients in and out of the cell:

2 1. Osmosis passive movement (no energy required) of water in or out of the cell. Water moves from high to low concentration. a. Hypotonic solution water moves into cell, cell swells. b. Hypertonic solution water moves out of cell, cell shrinks. c. Isotonic solution water in and out of cell is equal. No change. 2. Diffusion passive movement (no energy required) of any other substance in or out of the cell. Substance moves from high to low concentration. 3. Exocytosis requires active transport that uses energy (ATP) that moves material from out of the cell. 4. Endocytosis requires active transport that uses energy (ATP) to move material into the cell. Note: Active transport (also called facilitated transport) allows for moving substances from a low concentration to a high concentration. Cellular Respiration/Energy: Cells require a constant source of energy to carry out their life functions. The main source of energy for most living systems is the sun which processes the energy through the chemical process of photosynthesis. Photosynthetic organisms capture sunlight and transform it into a useable source of energy via the chemical bonds in the organic compounds it produces. Cells use some of this chemical bond energy to make ATP, the energy source for cellular work. Much of this energy is released as unusable heat. Catabolism: Chemical pathways that break down materials and release energy. The catabolic process of respiration transfers the energy stored in food molecules to ATP. Organisms use ATP molecules to capture and release small amounts of energy to fuel various bodily functions. The molecule contains the nitrogenous base adenine connected to three molecules of phosphorous. When ATP releases the terminal (end) phosphate, energy is released while forming a new compound ADP. ADP can be refitted with another phosphate to form ATP again. In order for the most efficient production of ATP to occur the cell must transfer this energy from the chemical bonds of the organic compounds to the ATP molecule with minimal loss. Objective 2 Organization of Living Systems - 6A Biology (6) structures of nucleic acids and functions in genetics / 6A-DNA and carrying genetic information Hint: The biggest problem with genetics is that there are often two or three names for the same thing that are used interchangeably. This makes it very confusing if you don t recognize this! The following terms below have been identified with all of their alias names as well. Heredity - The passing down of traits from parents to offspring. Genetic Diversity - The number of different genetic combinations available in a given gene pool (your heredity from your parents, grandparents, etc.). This is why we all don t look alike and why we do Punnet Squares to determine the probability that you are going to get a trait from mom or dad s side of the family! Gene - The basic unit of heredity, which is passed down from parent to offspring and can be transcribed into a protein chain. Also known as traits and sometimes referred to as DNA as well. We all have two different genes for each trait. You got one from your mom and one from your dad. Allele - One of two or more different genes that occupy the same place on a chromosome, allowing hereditary variation. Term is used interchangeably when referring to a gene or a trait. Example the

3 allele/gene for tallness (T) in pea plants. Allele is used when referring to one gene of the pair of genes we all have for each trait. Dominant Trait - A trait that produces the same phenotypic effect whether it was inherited homozygously or heterozygously; an allele/gene/trait that "masks" another. Dominant traits are written as the big letter in genetic problems and are always expressed. Example Tallness in pea plants (T) can be (T,T) or (T,t). Recessive Trait - A trait that only produces its phenotypic effect when inherited homozygously; a trait "masked" by a dominant trait. Recessive traits are written as the little letter in genetic problems. Recessive traits are only expressed when both genes are recessive. Example shortness in pea plants (t) the plants have to be (t,t). Incomplete Dominance (Codominance) when a given gene is not truly dominant or recessive or we have more than one dominant genes for the same trait. This results in a blending of traits. Example: Crossing a red flower (R,R) with a white flower (W,W) and getting pink flowers (R,W). Skin, hair and eye color in humans is controlled by multiple genes that blend together. Heterozygote/Hybrid - A organism who possesses two different alleles of a given gene. Example a pea plant that is (T,t). Homozygote/Purebred - An organism who possesses two identical alleles of a given gene. Example a pea plant that is (T,T) or (t,t). Genotype - The genetic makeup or constitution of an organism. Example (T,T) would be the genotype of the pea plant. Phenotype - The physical characteristics (what it looks like) associated with a certain genotype. Example the pea plant with (T,T) or (T,t) genotype would be tall. DNA (Deoxyribonucleic acid); the molecule that stores and passes on genetic information from one generation to the next. Located in the nucleus of the cell and also called genes. DNA gets its name from the sugar molecule contained in its backbone (deoxyribose), however it gets its significance from its unique double-stranded structure. There are four different nucleotide bases that occur in DNA: adenine (A), cytosine (C), guanine (G) and thymine (T). Exon - A segment of DNA that codes for a protein (amino acid) or regulates the activity of other genes. Intron - A non-coding segment of DNA; edited out during the transcription process. Mutation - A change in the DNA of an organism. Classified as insertion (addition of a base), deletion (subtraction of a base), or substitution (replacement of one base with another). Chromosomes - Rod-shaped structures found in the nucleus of every cell in an organism. The DNA of an organism is located on the chromosome. In males, all body cells have an X and a Y sex-chromosome, in addition to the 44 ordinary chromosomes (autosomes). In females, all body cells have two X sexchromosomes in addition to the 44 ordinary chromosomes (autosomes). Autosome - A chromosome that is not a sex chromosome (any one but the X and Y on chromosome # 23). Sex-linked (X-linked) - Linked to the X chromosome. X-linked disorders are recessive and occur only in males. This is because males have no second copy of the X chromosome to "obscure" the effects of the abnormal gene. If they inherit the defective gene then they get the problem. Hint: Think of chromosome as being a bus while the DNA is the passengers on the bus. Each of your body cells has 46 separated buses (chromosomes) arranged in23 pairs with each bus full of passengers (DNA/genes). The Exon is the driver of the bus.

4 Objective 2 Organization of Living Systems - 6B Biology (6) structures of nucleic acids and functions in genetics / 6B-replication of DNA and RNA Protein - A fundamental component of all living cells made up of amino acids and coded for by DNA. Amino Acid - One of the building blocks of proteins; there are 20 common amino acids (proteins). These are essential to maintaining human life. Have a balanced diet and eat your veggies since this provides the minerals so your cells can make these important proteins during protein synthesis! Nucleotide - A chemical (adenine, thymine, cytosine, and guanine) that makes up nucleic acid. On the DNA "ladder", adenine pairs with thymine (A-T) and cytosine pairs with guanine (C-G). In RNA, uracil replaces thymine (U-T). RNA - Ribonucleic acid; a class of nucleic acids similar to DNA but is only single-stranded and has a uracil base instead of a thymine base. RNA is the main genetic material used in the organisms called viruses, and is also important in the production of proteins in other living organisms. RNA can move around the cells of living organisms and thus serves as a sort of genetic messenger, relaying the information stored in the cell's DNA out from the nucleus to other parts of the cell where it is used to help make proteins. Replication The process of DNA making exact copies (replicates) of itself through protein synthesis which utilizes RNA. Transcription - The synthesis/building of messenger RNA from a DNA template. Translation - The synthesis of a protein from a messenger RNA template. Vector- A "vehicle" (virus, bacterium, etc.) used to get a foreign DNA sequence into a cell. Protein Synthesis - The DNA molecule unzips and messenger RNA copies the sequence (transcription) in the form of sets of three bases called codons, except replacing Thymine (T) with Uracil (U) which pairs up with Adenine (A). The mrna then carries the sequence to the ribosome which is located outside of the nucleus in the cytoplasm. There the transfer RNA and ribosome reads (translation) the sequence and formulates the specified amino acid (protein) which is then released into the cytoplasm for the cell to use. This information, detailing the specific structure of the proteins inside of our bodies, is stored in a set of molecules called nucleic acids (DNA and RNA). Objective 2 Organization of Living Systems - 6C -Biology (6) structures of nucleic acids and functions in genetics / 6C-DNA changes cause mutations. Genetic disorders are caused by mutations in a gene or a set of genes. Mutations are changes or glitches in the DNA sequence of a gene that can happen at any time. Most often mutations naturally occur during the replication or separation phases of mitosis (body cells) or meiosis (sex cells) when the process just doesn t occur correctly. However, environmental factors such as exposure to UV radiation or chemicals can cause mutations to occur. Mutations are good or bad depending upon if it increases or decreases survival of the organism. Some mutations do not cause disorders because the mutations are repaired. Our cells have mechanisms for repairing DNA if mistakes are made in the sequence or if the DNA is damaged. Since we have two copies of every chromosome (one from Mom and one from Dad), if one gene copy is mutant, the other copy usually can provide enough gene product to the organism for normal function. Karyotyping is done to determine if an organism has a genetic defect. Karyotype showing Trisome at chromosome # 21 Down s Syndrome

5 We can separate genetic disorders into four categories: A. Chromosome Abnormalities - In some disorders entire chromosomes, or large segments of them, are missing, duplicated, or otherwise altered. Down Syndrome and Turner's Syndrome are examples of this type of disorder. B. Single-Gene Disorders - Some disorders result when a mutation causes the product of a single gene to be altered or missing. An example of this kind of disorder is sickle-cell anemia. C. Multifactorial Disorders -Result from mutations in multiple genes, often coupled with environmental causes. The complicated bases of these diseases make them difficult to study and to treat. Heart disorder, diabetes and cancer are examples of this type of disorder. D. Mitochondrial Disorders -These relatively rare disorders are caused by mutations in non-chromosomal DNA located within subcellular organelles, the mitochondria. There are multiple copies in a single cell's cytoplasm, all transmitted by the mother in the ovum. Objective 2 Organization of Living Systems - 6D Biology (6) structures of nucleic acids and functions in genetics / 6D-genetic variations in plants and animals. Genetics is based on predictable patterns of inheritance. Understanding genetics depends on understanding these patterns, which are based on possible combinations of gametes. Punnett squares provide a way to determine these combinations which enables us to determine the probability of the offspring having a particular trait. The genotype of each parent (F 1 ) is crossed to predict the traits of the offspring (F 2 generation). A. Monohybrid Crosses - in Mendelian genetics, each trait has two alleles. In monohybrid crosses, only one trait is involved at a time. Each parent contributes two alleles, producing four possible combinations for the one trait. B. Dihybrid crosses - involve solving for two traits at a time in the same Punnett square. A dihybrid cross involves two alleles per trait for two different traits, for a total of four alleles.

6 Objective 2 Organization of Living Systems - 8C - Biology (8) applications of taxonomy / 8C-characteristics of kingdoms Classification grouping objects according to their characteristics Taxonomy the branch of biology that names and groups organisms according to their characteristics and evolutionary history King--Phillip--Came--Over--For--Good--Soup Binomial nomenclature 2 name system uses the genus and the species to identify an organism. (homo sapien) Modern taxonomists now classify organisms according to their phylogeny, or evolutionary history. This has become a branch of biology called systematics and uses the following information: 1. Fossil record - ancestors 2. Morphology similar body structures 3. Embryological patterns of development 4. Chromosomes and macromolecules (dna and proteins) 5. Cladistics is the classification of organisms because of a shared derived characteristic (such as feathers) that is thought to only have evolved in one group from a common ancestor

7 Objective 2 Organization of Living Systems - 10A -Biology (10) living systems / 10Ainterpret the functions of systems in organisms There are 11 major systems in the human body. All are important for survival and serve as an important function of homeostasis, or equilibrium. They are as follows: 1. Circulatory - Structure: The circulatory system consists of the heart, arteries (carry blood away from the heart), veins (carry blood to the heart), capillaries (where nutrient and gas exchange occurs with tissue), and blood. Function: The function of the circulatory system is to transport blood to every part of the body. In the blood are all of the necessary gases, nutrients, and waste products; which are all transported to the necessary parts of the body.

8 2. Digestive Structure: The digestive system begins with the mouth. It continues with the esophagus, stomach, small intestine, large intestine, and ends with the rectum. There are several organs that are associated with the digestion process. The liver, among other functions, produces bile (a digestive enzyme). The gall bladder stores the bile. The pancreas also secretes digestive enzymes and hormones. Function: The function of the digestive system is to digest food and provide vital nutrients to the body. It also helps to regulate metabolism, as well as eliminate wastes. 3. Nervous Structure: The nervous system is broken down into two parts: the central nervous system and the peripheral nervous system. The brain and spinal cord combine to create the central nervous system (acts as the body s control center and coordinates body s activities). The nerves that carry messages to and from the central nervous system to the entire body makes up the peripheral nervous system. Function: The nervous system controls all bodily activities. 4. Endocrine Structure: The endocrine system consists of a network of glands including the pituitary, thyroid, thymus, pancreas, testes, ovaries, adrenal, and parathyroid glands. Function: The endocrine system consists of glands that secrete hormones that play a key role in the regulation of digestion, metabolism, and homeostasis. 5. Reproductive Structure: The male reproductive system consists of the testis (produce sperm), vas deferens (tube to transport sperm), urethra (continuation of vas deferens), and the penis. The female reproductive system consists of the ovary (produces eggs), the uterus, and the vagina. Function: The function of the reproductive systems in males and females is to perpetuate the species through reproduction. 6. Integumentary (skin) Structure: The skin is composed of two parts, the epidermis and the dermis. The epidermis is the outer, thinner portion of the skin. The dermis is the inner, thicker portion of the skin. Also associated with the skin are melanin (pigment in the skin), keratin (dead, waterproofing cells), and hair follicles. Function: The skin has several vital roles in maintaining equilibrium within the body. The skin is responsible for regulating your body temperature. It also serves as a protective layer to the underlying tissues. 7. Skeletal Structure: The skeleton is comprised of two parts, the axial skeleton, and the appendicular skeleton. The axial skeleton is made up of the skull, the vertebral column, the ribs, and the sternum. The appendicular skeleton are the bones of the arms and legs, including the shoulders and pelvic girdle. Joints, ligaments (connects bones to bones), and tendons (connects muscles to bones) are also associated with the skeletal system. Function: The skeletal system provides a framework for the tissue of the body. It also protects the upper organs. Muscles are anchored to the bones to allow for movement. Bones also produce blood cells, and store vital minerals. 8. Respiratory Structure: The first part of the respiratory system is the trachea, this is the passageway of air from the mouth or nasal cavity. The trachea then divides into two bronchi, with are the tubes that lead to the lungs, which then branch into bronchioles that lead to the tiny air sacs called alveoli, where gas exchange occurs with the blood. Function: The purpose of the respiratory system is to provide the body with oxygen, and also to dispel carbon dioxide from the body.

9 9. Muscular Structure: There are three types of muscles: smooth, cardiac, and skeletal. Smooth muscle is found in internal organs and blood vessels. Cardiac muscle is found in the heart. Skeletal muscles are attached to bones. Muscles are also voluntary (skeletal muscle) or involuntary (smooth and cardiac). Function: Smooth muscle allows for the contraction of organs (moves food along the intestines) and blood vessels (pushes blood through). Cardiac muscle is responsible for the pumping of the heart. Skeletal muscle allows for all movement of the body. 10. Excretory/Urinary Structure: The excretory system consists of the kidneys (filters the blood), the ureters (tubes that lead from kidneys to urinary bladder), the urinary bladder (where urine is stored), and the urethra (tubes that lead from the urinary bladder to the outside of the body). Function: The function of the excretory system is to filter the blood and remove major waste products such as ammonia and urea. It is also responsible for regulating the ph (acidity level) of the blood. 11. Immune/Lymphatic Structure: The immune system consists of a variety of structures found throughout the body. The lymph nodes and lymph vessels are found throughout the body and help to filter out antigens (disease causing microorganisms). The tonsils, thymus gland, spleen, and bone marrow are also involved in the immune system. Function: The function of the immune system is to protect the body from infections and antigens. Objective 2 Organization of Living Systems - 10B -Biology (10) living systems / 10Binterrelationships of organ systems 1. Levels of organization in multi-cellular organisms from simplest to most complex cell, tissues, organs, and organ systems. 2. Interactions between the different systems for a variety of life functions, such as transporting oxygen, digesting food, physical body movement. All systems must work together for the organism to function and survive. The only system that an organism does not need for survival is the reproductive system. Example transporting oxygen uses the respiratory and cardiovascular systems along with the muscular system (diaphragm) and the nervous system. 3. The characteristics of a system in equilibrium are when all components or parts of the system that interact together are stable and functioning normally. 4. Homeostasis is the process of maintaining equilibrium in an organism. Examples of homeostasis that can be measured are heart rate, respiration, temperature, cell counts. If these are elevated or suppressed (below normal), then the body is not in homeostasis/equilibrium. (NOTE: homeostasis and equilibrium terms are often used interchangeably!) 5. Homeostasis uses the process of negative feedback in order to maintain the equilibrium (stability) of the organism. For negative feedback to have occurred the process must STOP!

10 6. Examples of negative feedback processes are perspiring and shivering, regulating blood glucose levels, and maintaining turgor pressure in plants. ** For negative feedback to have occurred the process must STOP! 7. A negative feedback process forms a loop/cycle. For example your body becomes dehydrated so homeostasis kicks in and makes the body feel thirsty. You then get drink some fluids (water, etc.) until your body is re-hydrated. Homeostasis then signals you to stop drinking fluids (this is the negative feedback STOP signal). Your body is now in equilibrium since you are no longer dehydrated. 8. The process of maintaining water equilibrium in plant and animal cells occurs through regulating processes, such as diffusion (movement of substances into and out of cells, osmosis (movement of water in/out of cells), and turgor pressure (cell pressure wilted plants). Resource: