Biology 30 Review - Molecular Biology & Protein Synthesis

BIOLOGY 30DIPLOMA REVIEWBy: Mrs. Pilipchuk Molecular Biology(DNA and Protein Synthesis) Unit C Structure of DNA and RNA DNA is made up of 2 strands of nucleotides. Nucleotides = phosphate, sugar, and a nitrogenous base (Adenine, Thymine, Guanine, Cytosine). RNA is made up of 1 strand of nucleo...

BIOLOGY 30DIPLOMA REVIEWBy: Mrs. Pilipchuk Molecular Biology(DNA and Protein Synthesis) Unit C Structure of DNA and RNA DNA is made up of 2 strands of nucleotides. Nucleotides = phosphate, sugar, and a nitrogenous base (Adenine, Thymine, Guanine, Cytosine). RNA is made up of 1 strand of nucleotides. Uracil replaces Thymine as a nitrogenous base. 3 The Central Dogma This dogma forms the backbone of molecular biology and is represented by the stages below. DNA replicates DNA codes are transcribed in the production of messenger RNA (mRNA) The mRNA is migrates from the nucleus to the cytoplasm mRNA carries coded information to ribosomes for use in protein synthesis (translation) DNA Replication DNA Replication is semiconservative: Each strand acts as a template for the synthesis of a new DNA molecule by the sequential addition of complementary base pairs. A new DNA strand is generated by DNA polymerase III that is a complementary sequence to the parental DNA. Each newly formed DNA molecule ends up with one of the original strands and one newly synthesized strand. mRNA Synthesis (Transcription) One strand of the DNA double helix is used as a template by the RNA polymerase to synthesize mRNA. Initiation – Transcription starts when RNA polymerase binds to the segment of DNA in a region called the promoter. The promoter makes sure it can only bind in front of a gene. Elongation - A mRNA molecule forms in the 5’ to 3’ direction as nucleotides match the exposed DNA template. Termination - Synthesis of mRNA (codon) continues until it reaches the end of a gene called the termination sequence. The new mRNA molecule then travels to the cytoplasm. Protein Synthesis (Translation) In the cytoplasm, ribosomes move along the mRNA molecule and "read" its sequence three nucleotides at a time (codon) Each amino acid is specified by the mRNA's codon A sequence of three complementary nucleotides (anticodon) linked to tRNA carry along the corresponding amino acid Amino acid chains = proteins = building blocks of life The chain starts at the mRNA start codon and ends at a stop codon Summary of Central Dogma TAC AAA AGA CAT DNA template AUG UUU UCU GUA mRNA molecule UAC AAA AGA CAU tRNA molecules Amino acid sequence : Methionine + Phenylalanine + Serine + Valine * Note that the amino acids are specific to the mRNA codons. Therefore if a codon is changed due to mutation the amino acid changes, causing a change in the protein. Different mutations can occur during replication, transcription and translation. Some are silent, some cause a single amino acid to be changed, while others cause an entire frameshift mutation. Recombinant DNA Technology Recombinant DNA technology involves placing genetic information from one organism into the chromosomes of another organism. The aim of this technology is to “trick” the genetically engineered cell into producing some protein that it cannot make naturally. DNA restriction endonucleases/enzymes cut strands of DNA, and DNA ligase glues strands in. Released Diploma Questions Multiple choice # 23 - 27 Answers: MC23 = B MC26 = D MC24 = C MC27 = A MC25 = C Cell Division(Mitosis and Meiosis) Unit C Cell Cycle 10% of cell cycle Mitosis: Nuclear division. Cytokinesis: Cytoplasm division. 90% of cell cycle Interphase: Growth phase G1 gap (growth) the phase after mitosis S phase (synthesis) chromosomal DNA is replicated G2 gap (growth) after synthesis and before mitosis DNA synthesis cytokinesis 46 46x2 G1 S G2 P M A T G1 Quantity of DNA in a cell during cell cycle Mitosis (IPMAT-C) Interphase - Growth, DNA replication, regular cell functions Prophase Chromatin shortens & thickens, chromatids joined by centromere, centrioles begin to migrate to opposite sides, nuclear membrane & nucleolus disappear, spindle fibers generate from centrioles Metaphase Centrioles move opposite each other, spindle fibers attach to chromatids, chromatids line up on equatorial plate Anaphase Chromatids separate at centromeres, chromatids -> chromosomes, chromosomes move to opposite poles Telophase Chromosomes decondense (chromatin), nuclear membrane & nucleolus reform, spindle fibers reform, cleavage furrow forms at the equator Cytokinesis 2 daughter cells separate Meiosis During interphase, the chromosomes replicate then go into Meiosis I. Prophase l: Crossing over Nuclear membrane disappears Centrioles move to poles and spindle fibers form Metaphase l: - Homologous chromosomes attach themselves to the spindle fibers and line up along the equatorial plate Tetrads attach to the spindle fibers. Anaphase l: - Chromatid pairs of each tetrad move to opposite poles (homologous chromosomes separate - segregation) Sister chromatids remain attached and begin migrating to the poles (humans have 23 doubled chromosomes at each pole) Telophase l: - Secondary gametocytes formed at the end of telophase I when cytokinesis is completed - Cells have one homologous pair, sister chromatids have not yet separated - Chromosomes do not uncondense to form chromatin - Nuclear membrane forms around dyads of sister chromatids - Cytokinesis begins The 2 daughter cells have a haploid (n) chromosome number but they are doubled called one half of 2n. Meiosis cont’d. Interphase: - Short resting phase - Chromosomes do not completely unwind (incomplete decondensation) no DNA replication Prophase II: - Nuclear membrane disappears, and the spindle fibers form. Metaphase II: Chromatid pairs (dyads) align at the equator of the cell. Spindle fibers attach to the centromeres Anaphase II: Centromeres split and the sister chromatids move to opposite poles of the cell. Telophase ll: Cytokinesis and complete decondensation is completed forming four haploid cells called monads - each vary in structure Telophase II produces four granddaughter cells Non Disjunction The unequal distribution of chromosomes. 2 homologous chromosomes move to the same pole during meiosis. A nondisjunction results in one daughter cell having an extra chromosome called trisomy and another daughter cell missing one called monosomy. Down’s syndrome: 47 chromosomes; trisomy 21 Edward’s syndrome: trisomy of the 18th pair Patan’s syndrome: trisomy of the 13th pair Turner’s syndrome: monosomy X - female with 45 chromosomes Klinefelter’s syndrome: has XXY, males Triple X syndrome: has trisomy X or XXX – females XYY chromosome disorder: XYY males that may have severe autistic spectrum disorders Alternation of Generations Cycling between diploid (2N) and haploid (N) Mosses Ferns & flowering plants Released Diploma Questions Multiple choice # 15 – 20 Answers: MC15 = D MC18 = A MC16 = A MC19 = C MC17 = A MC20 = C The Basis of Heredity(Genetics) Unit C Genetics Genotype: The genes that an organism contains for a specific trait. R = Round seeds, r = wrinkled seeds RR or Rr or rr Homozyg. dom. Heterozyg. Homozyg. rec. Phenotype: The observable traits of an individual. Round seeded phenotype (RR or Rr genotype), wrinkled seeded phenotype (rr genotype) Mendelian Genetics – Monohybrid Cross P1 – TT x tt (pure breeding) F1 – Tt x Tt F2 – ¾ tall; ¼ short (3:1 ratio) Test Cross Process used to determine an unknown genotype Only necessary when an individual demonstrates the dominant phenotype Dominant phenotype could be either RR or Rr Test is accomplished by crossing the unknown with a homozygous recessive individual If progeny are ½ dominant and ½ recessive then the unknown was heterozygous If all progeny are the dominant phenotype then the unknown was homozygous Mendelian Genetics: Dihybrid Cross Dihybrid crosses: The study of 2 traits in a simple cross. Use the FOIL technique to make gametes Pea color: Y (yellow), y (green) Pea shape: R (round), r (wrinkled) Calculate the F1 and F2 genotype and phenotype frequencies of the following cross: P1: RR YY x rr yy F1: Rr Yy x Rr Yy F2: 9/16 round & yellow, 3/16 round & green, 3/16 yellow & wrinkled, 1/16 green & wrinkled (9:3:3:1) Pedigrees A pedigree chart is a diagram which shows how a particular trait is transmitted from generation to generation in a family. Pedigrees are used to represent the result of crosses when few individuals are involved Pedigree symbolsare provided in the data booklet Pleiotropic Genes Pleiotropic genes are genes that affect more than one characteristic. The most common trait is called the wild type. Non wild type are called mutant. eg. Eye color for Drosophilia (fruit fly): E1 (wild type or red) E2 (apricot) E3 (honey) E4 (white) Order of dominance: E1 > E2 >E3 > E4 Phenotype Possible genotypes Wild type E1E1, E1E2, E1E3,E1E4 Apricot E2E2, E2E3, E2E4 Honey E3E3, E3E4 White E4E4 Dominance Incomplete Dominance: When the alleles for a gene are equally dominant, they can interact to produce a new phenotype. An intermediate phenotype develops from the interaction of alleles. (appears to be blending) eg. Snapdragons (flower) CR CR (red), CW CW (white), CR CW (pink) Co-dominance: When both alleles of a gene are expressed at the same time. (no masking) eg. Cattle: Hr (red haired), Hw (white haired) eg. Blood types Hr Hr (red bull) x Hw Hw (white cow) 🡪 Hr Hw (roan) Roan – mixture of red and white hairs scattered on the body Polygenic traits: Inherited characteristics that are affected by more than one gene. eg. human hair color, skin color and height. Epistatic genes: Genes that mask the expression of other genes. eg. Dog coat color. B (black) or b (brown) W (prevents pigmentation) w (allows pigmentation) Bb ww (black dog) Bb Ww (white dog) Sex Linkage F1 cross = Rr (male) x Rr (female) F2 = 3/4 red eyed 1/4 white eyed Followed all Mendelian inheritance patterns except that only the males in the F2 offspring had white eyes. Gene Linkage Linked genes do not always stay together in gamete formation. Crossing over can occur during meiosis eg. Aa Bb (linked genes) Parental gametes: AB , ab Recombinant gametes: Ab , aB Construct a gene map from the following data Genes A B C D A _ 12 15 4 B 12 _ 3 8 C 15 3 _ 11 D 4 8 11 _ Released Diploma Questions Multiple choice # 21 and 22 Numerical response # 4 Answers: MC21 = A MC22 = A NR4 = 0.50 Reproduction and Development Unit B Male Reproductive System Hormone Control At puberty the hypothalamus releases GnRH (gonadotropin -releasing hormone) GnRH activates the pituitary causing the release of FSH and LH FSH acts on sperm producing cells in the seminiferous tubules LH stimulates the interstitial cells to make testosterone Once high levels of testosterone is detected by the hypothalamus, a negative feedback system is activated Female Reproductive System Hormone Control At puberty, the hypothalamus releases GnRH (gonadotropin releasing hormone) GnRH stimulates pituitary where FSH and LH are stored During the follicular phase of the menstrual cycle, FSH is released and carried by blood to the ovary This stimulates follicle development Developing follicle releases estrogen Estrogen acts on pituitary and decreases FSH release Hormone Control Developing follicle produces estrogen High levels of estrogen alone stimulates the hypothalamus, and a spike in LH and FSH is seen. The high levels of LH cause ovulation The corpus luteum that forms after ovulation releases estrogen and progesterone The presence of both together inhibits the hypothalamus and FSH and LH levels fall Menstrual Cycle Fertilization, Pregnancy, Birth Fertilization occurs in the fallopian tubes Blastocyst travels down and implants on the endometrium Pregnancy is maintained by the corpus luteum for the first 3 months (maintained by hCG) and the placenta for the rest of the pregnancy The gastrula layers (ectoderm, mesoderm, endoderm) form different structures There are three different stages of development in which the different structures are formed: 1st trimester, 2nd trimester, and 3rd trimester Parturition (birth) is initiated by a drop in progesterone and increase in oxytocin and relaxin Prolactin produces milk after the baby is born and oxytocin promotes the flow of milk Released Diploma Questions Multiple choice # 6 - 7, 9 - 14 Numerical response # 3 Answers: MC6 = C MC12 = A MC7 = D MC13 = B MC9 = B MC14 = D MC10 = D NR3 = 321 MC11 = B The Endocrine System Unit A Hypothalamus and Pituitary Hormones Hormone Location of Production Target Releasing hormones (ex. GnRH and TRH) Hypothalamus Anterior Pituitary TSH Anterior Pituitary Thyroid gland ACTH Anterior Pituitary Adrenal cortex hGH Anterior Pituitary Most cells FSH Anterior Pituitary Gonads LH Anterior Pituitary Gonads PRL Anterior Pituitary Mammary glands MSH Anterior Pituitary Melanocytes in skin Oxytocin Hypothalamus – Stored in Posterior pituitary Uterus and mammary glands ADH Hypothalamus – Stored in Posterior pituitary kidneys Thyroid, Parathyroid, Pancreatic and Adrenal Hormones Hormone Location of Production Target Insulin Beta cells of Islets of Pancreas Body cells and blood glucose Glucagon Alpha cells of Islets of Pancreas Glycogen in liver Epinephrine and norepinephrine Adrenal medulla Heart rate, cell metabolism, glycogen Cortisol Adrenal cortex Amino acids Aldosterone Adrenal cortex Kidneys Thyroxine and T3 Thyroid Cell metabolism Calcitonin Thyroid Calcium in blood PTH (parathyroid hormone) Parathyroid glands Calcium in bones Review the effect of all of these hormones and review the reproductive hormones as well (estrogen, progesterone, testosterone). Feedback Loops Feedback loops can be both positive and negative Released Diploma Questions Multiple choice # 5 and 8 Numerical response # 2 Answers: MC5 = A MC8 = A NR2 = 1245 (any order) The Nervous System and Senses Unit A Neurons A neuron is a nerve cell. They conduct impulses from the external environment to the brain/spinal cord. If a neuron has a myelin sheath, it is considered white matter. If the myelin contains neurilemma, the neuron can repair itself if damaged. If a neuron lacks myelin, it is considered grey matter and damage is irreversible. 1. Presynaptic Terminal 2. Myelin 3. Axon 4. Node of Ranvier 5. Cell Body (Soma) 6. Dendrites 7. Nucleus Action Potentials/Synapse The impulses are carried by the flow of ions in and out of the neuron. Sodium channels flow into the cell to depolarize it, then potassium channels flow out to repolarize. When the action potential reaches the end of the neuron, it must cross the synapse (gap). Acetylcholine travels across the gap to open the sodium channels of the postsynaptic neuron. Cholinesterase then breaks up any acetylcholine left in the synapse. Reflex Arcs Involves 5 basic parts : sensory receptor, sensory neuron, interneuron (spinal cord), motor neuron, effector (muscle or gland) receptors on the external body detect changes in the environment. The sensory neuron passes the signal on to the interneuron in the spinal cord. The spinal cord relays a message to the motor neuron to move your hand, all in less than a second! Sympathetic/Parasympathetic Nervous System The sympathetic nervous system prepares your body for stress. When stimulated it activates the “fight or flight response”. Changes to your body include: pupil dilation, increased breathing and heart rate, and secretion of epinephrine. The parasympathetic nervous system brings your body back to a normal state after stress. The Brain OCCIPITAL LOBE Interpreting visual information. FRONTAL LOBE Concerned with reasoning, planning, parts of speech and movement (motor cortex), emotions, problem-solving, personality, and intellectual activities. TEMPORAL LOBE Concerned with perception and recognition of auditory stimuli (hearing) and memory (hippocampus). Interpreting sound or auditory information. Smell interpretation. PARIETAL LOBE Concerned with perception of stimuli related to touch, pressure, temperature, taste and pain. Cerebellum: Controls balance, coordination of limb movements, and muscle tone. The pons connects the 2 regions of the cerebellum. Medulla oblongata: Regulates heart rate, breathing rate, diameter of blood vessels. The Eye Cornea – Transparent, dome shaped window covering the front of the eye. Provides 2/3 of theeye's focusing power Sclera – The “white” of the eye, Protective layer and maintains eye shape Aqueous humor – Thin, watery fluid that fills the space between the cornea and the iris that nourishes the cornea and lens. Choroid – Composed of layers of blood vessels that nourish the back of the eye. Iris- Colored part of the eye that controls light levels inside the eye. Embedded with tiny muscles that dilate (widen) and constrict (narrow) the pupil size.   Lens- Focus light on the retina. Vitreous humor- thick, transparent substance that fills the center of the eye. Retina – Multi-layered sensory tissue that lines the back of the eye. Contains photoreceptors called rods (black and white) and cones (colour). Fovea Centralis – Area on the retina that contains many cones. Blind spot – area of the eye where the optic nerve attaches to the retina. 51 The Ear Hearing: Pinna, Auditory canal, tympanic membrane, ossicles, oval window, cochlea, auditory nerve, vestibule. Ear Equilibrium and balance: Semicircular canals,vestibule, Eustachian tube. Released Diploma Questions Multiple choice # 1 - 4 Numerical response # 1 Answers: MC1 = C MC4 = C MC2 = D NR1 = 3124 MC3 = A Population and Community Dynamics Unit D Hardy-Weinburg p +q = 1.0 p2 + 2pq + q2 = 1.0 p = Frequency of the dominant allele in the population. (“A”) q = Frequency of the recessive allele in the population. (“a”) p2= Frequency of homozygous dominant genotypes. (“AA”) q2= Frequency of homozygous recessive genotypes. (“aa”) 2pq = Frequency of heterozygous genotypes. (“Aa”) Mechanisms for Evolution Random genetic drift – when a natural disaster wipes out a large portion of the population. Gene flow – Natality, mortality, immigration and emigration. Mutation – can be beneficial or harmful. Non-random mating – lowers genetic variability. Natural selection – Competition for limited resources, survival of the fittest. Distribution/Density Interspecific/Intraspecific competition D = N S Rate of density change = ∆ density ∆ time Population Growth Patterns Natality – the # of offspring of a species born in one year Mortality - # of individuals of a species that die in one year Immigration - # of individuals of a species moving into an existing pop Emigration - # of individuals that move out of an existing pop Capture-Recapture: # organisms marked = # marked recaptured Total Population Total # of individuals in second sample Per capita growth rate (cgr): cgr = [births + immigration]–[deaths + emigration] x 100 initial # of organisms (N) cgr = ∆N N K/r Selected Populations r-Selected:- J-shaped growth curves- “quantity over quality” offspring- Short life span- Little/no parental care- Able to reproduce quickly in life.- Ex. Insects K-Selected:- S-shaped growth curves- “quality over quantity” offspring- Long life span- Parental care- Able to reproduce later in life.- Ex. Most mammals 59 Competition/Predation/Symbiosis Competition: Intraspecific/Interspecific Predation: mimicry, camouflage, co-evolution Symbiosis: Parasitism, Commensalism, Mutualism Succession Slow, orderly progressive replacement of one community by another during the development of vegetation in any area. Succession starts with a pioneer community, after which seral stages replace one another until a climax community is reached. 2 types of succession: Primary succession Occurs on ground where no community has existed before Ex. On a newly formed volcanic island or land released by glacier retreat Secondary succession Occurs following partial or complete destruction of a community Ex. Re-growth after a severe forest fire Released Diploma Questions Multiple choice # 28 - 31 Numerical response # 5 Answers: MC28 = D MC31 = B MC29 = B NR5 = 0.20 MC30 = C