BIO B 1 Cell Growth Reproduction BIO B
BIO. B. 1 Cell Growth & Reproduction BIO. B. 1. 1. 1 Eligible Content Describe the events that occur during the cell cycle: interphase, nuclear division (mitosis and meiosis) and cytokinesis.
Cell Cycle Repeating sequence of cell growth and division in the life of a cell.
Interphase Time period between cell divisions.
Mitosis Type of cell division that produces two genetically identical daughter cells. Division of the nucleus.
Meiosis Type of cell division that results in the formation of gametes (egg & sperm) Type of cell division that reduces the chromosome number in half
Cytokinesis Division of the cytoplasm and organelles.
Events of the Cell Cycle Interphase: Time period between cell divisions 1) Cell Growth 2) DNA Duplicates 3) Preparation for Mitosis Interphase - Mitosis - Cytokinesis G 1 - S - G 2 - M - C
Events of the Cell Cycle Mitosis: Division of the nucleus Prophase – Metaphase – Anaphase – Telophase
Events of the Cell Cycle Cytokinesis: Division of the cytoplasm and organelles. Plant Cell – Cell plate forms dividing the two cells Animal Cell – Cell pinches inward forming a cleavage furrow
Meiosis • Occurs in germ cells (testes in males and ovaries in females) • Reduces the chromosome number in half / Produces gametes • Human somatic cells have 46 chromosomes but their gametes (egg and sperm) have 23 chromosomes • Meiosis I and Meiosis II
Mitosis • Occurs in somatic cells (all body cells except germ cells) • Type of cell division that produces two genetically identical daughter cells. • 4 stages: (PMAT) Prophase Metaphase Anaphase Telophase
BIO. B. 1 Cell Growth and Reproduction BIO. B. 1. 2. 1 Eligible Content Describe how the process of DNA replication results in the transmission and/or conservation of genetic information.
DNA Replication • DNA replication is a process in which a cell makes an exact copy of its DNA • Base Pairing Rules: A- T C- G • DNA helicase is the enzyme that unwinds the DNA • Nucleotides are added following the base pairing rules. DNA polymerase adds nucleotides following the base pairing rules
A T T A G C C G A T C G T A G C A T How does DNA replication result in the transmission and/or conservation of genetic information? DNA replication ensures that when a cell divides, a complete copy of DNA goes to each daughter cell. Thus, transmitting it to the next generation.
BIO. B. 1 Cell Growth and Reproduction BIO. B. 1. 2. 2 Eligible Content Explain the functional relationship between DNA, genes, alleles and chromosomes and their role in inheritance.
Understanding of Inheritance • To understand the relationship between DNA, genes, alleles and chromosomes lets first begin with an understanding of the genome.
Genome – All of the genetic material contained within an organism Chromosome – DNA and protein complex that contains individual units called genes DNA – Genetic material of a cell Gene – Segment of DNA that contains the instruction for a protein (particular trait) Allele – Alternative form of a gene Genome Chromosome DNA Gene Allele
BIO. B. 2 Genetics BIO. B. 2. 1. 1 Eligible Content Describe and/or predict observed patterns of inheritance (ie. dominant, recessive, codominance, incomplete dominance, sex-linked, polygenic and multiple alleles).
Key Terms: Dominant Allele - When one allele is completely dominant over the other allele. Represented by a capital letter. Recessive Allele – Describes an allele that is expressed only when there is no dominant allele present. It is only expressed when paired with another recessive allele. Represented by a lower case letter. Ex. G = green g = yellow Green pods are dominant over yellow pods
Key Terms: (continued) Genotype – The gene combination or set of alleles that determines the phenotype. Phenotype – The physical appearance or detectable trait determined by the genotype. Ex. Genotype GG Gg gg Phenotype Green Yellow
Key Terms: (continued) Heterozygous – Describes an individual that carries two different alleles of a gene. (Also referred to as a hybrid) Ex. Gg = Heterozygous Homozygous – Describes an individual that carries two of the same alleles of a gene. (Also referred to as a purebred) Ex. GG or gg = Homozygous Punnett Square – A graphic used to predict the outcome of a genetic cross.
Complete Dominance Describes a pattern of inheritance in which one allele is completely dominant over the other allele. Ex. Trait = Pod Color G = green g = yellow What will be the result of a cross between two heterozygous green pea pod pea plants? Gg x Gg G g Genotypic Ratio = 1/4 GG : 2/4 Gg : 1/4 gg G GG Gg gg Phenotypic Ratio = 3/4 Green : 1/4 Yellow
Incomplete Dominance Describes a pattern of inheritance in which the offspring has a phenotype that is intermediate between the traits of the two parents. Think “Blending” Ex. Four O’clock Flowers RR = Red R’R’ = White RR’ = Pink What will be the result of a cross between two heterozygous four o’clock flowers? RR’ x RR’ R RR RR’ R’R’ Genotypic Ratio = 1/4 RR : 2/4 RR’ : 1/4 R’R’ Phenotypic Ratio = 1/4 Red : 2/4 Pink : 1/4 White
Co-dominance Describes a pattern of inheritance in which both alleles are expressed in a heterozygous individual. Both alleles for the same gene are fully expressed. Two traits can appear at the same time. Ex. Fur color of cows R = Red W = White RW = Roan (Red and White Fur) RR x RW R RR RR W RW RW Genotypic Ratio = 2/4 RR : 2/4 RW Phenotypic Ratio = 1/4 Red : 2/4 Pink : 1/4 White
Multiple Alleles Describes a pattern of inheritance in which genes have three or more possible alleles. Ex. ABO Blood Groups AA or AO = Type A BB or BO = Type B AB = Type AB OO = Type O If a man and woman get married and have children. The man has type B blood and the woman has type O blood. Can the couple have a child the has type O blood? Explain B O O BO OO There is a 50% chance that the couple can have a child with type O blood if the man’s genotype is BO.
Sex-Linked Traits Describes a pattern of inheritance that involves a gene located on the X chromosome. The Y chromosome is much shorter than the X chromosome and lacks that portion. Ex. Hemophilia Unaffected Male XHY Unaffected Female XHXH Affected Male Xh. Y Carrier Female XHXh Affected Female Xh. Xh Suppose a female affected by hemophilia and an unaffected male plan to have children. Predict the probability of any of their potential offspring being affected by hemophilia. In your answer, be sure to identify the probability for both male and female offspring. XH Y Xh X HX h X h. Y X h x X H Y There is no chance that if they have a girl that the girl could have hemophilia. A girl would only be a carrier. If the couple had a boy, the boy would definitely have hemophilia.
BIO. B. 2 Genetics BIO. B. 2. 1. 2 Eligible Content Describe processes that can alter composition or number of chromosomes (ie. crossing over, nondisjunction, duplication, translocation, deletion, insertion and inversion)
Crossing Over The exchange of genetic material on corresponding chromatids that occurs during prophase I of meiosis
Chromosomal Mutations Errors in the exchange during crossing over Deletion – Occurs when a piece of chromosome is lost Duplication – Occurs when a piece remains attached to its homologous chromosome. Inversion – Occurs when a piece of chromosome reattaches to its original chromosome but in a reverse direction. Translocation – Occurs when a chromosome piece ends up in a completely different non-homologous chromosome
Nondisjunction The failure of homologous chromosomes to separate properly during meiosis I or failure of chromatids to separate properly during meiosis II
BIO. B. 2 Genetics BIO. B. 2. 3. 1 Eligible Content Describe how genetic mutations alter the DNA sequence and may or may not affect the phenotype (eg. Silent, nonsense, frameshift)
Silent A mutation that is a change in a single nucleotide. A mutation that results when a codon is changed but the new codon produces the same amino acid. Has no effect on the genes function.
Missense A mutation that is a change in a single nucleotide. A mutation that results when a codon is changed and the new codon codes for a different amino acid
Nonsense A mutation that is a change in a single nucleotide. A mutation that results when a codon is changed and the new codon produces a stop signal.
Frameshift A mutation that results when an insertion of deletion of a nucleotide causes the reading frame to shift. The remaining sequence may be read as different codons.
BIO. B. 2 Genetics BIO. B. 2. 2. 1 Eligible Content Describe how the processes of transcription and translation are similar in all organisms.
What is the Genetic Code? The genetic code is a set of three-letter combinations of nucleotides called codons, each of which corresponds to a specific amino acid, start signal or stop signal. The genetic code is universal and applies nearly to all organisms.
Gene Expression A process that uses DNA to make protein
Transcription • A process that uses DNA to make m. RNA • Takes place in the nucleus
Translation • A process that uses m. RNA to make protein. • Takes place in the cytoplasm
BIO. B. 2 Genetics BIO. B. 2. 4. 1 Eligible Content Explain how genetic engineering has impacted the fields of medicine, forensics and agriculture. (eg. Selective breeding, gene splicing, cloning, genetically modified organisms and gene therapy)
Selective Breeding Humans choosing organisms to breed in order to receive specific traits.
Gene Splicing Removing a gene from one organism and replacing it in the DNA of another organism.
Cloning Creating an exact genetic duplicate of an organism
Genetically Modified Organisms An organism containing genetic material that has been altered to produce a desired characteristic. Examples: Corn Salmon Soybeans
Gene Therapy A technique that places a gene into a cell to correct a hereditary disease or to improve the genome.
BIO. B. 3 Theory of Evolution BIO. B. 3. 1. 1 Eligible Content Explain how natural selection can impact allele frequencies of a population
Natural Selection Occurs when individuals with favorable traits are more likely to survive, reproduce and pass those favorable traits to their offspring than those organisms that lack those traits. Examples: Deer with thick fur are well suited to live in a cold environment. to Some cheetahs can run faster than other cheetahs and will therefore be more likely catch their prey
Peppered Moths
Allele Frequency The percentage of a population of a species that carries a particular allele on a given chromosome locus. 100 Individuals 30 AA 50 Aa 20 aa Total % of Dominant Alleles AA - 30 x 2 = 60 Aa - 50 x 1 = 50 60 + 50 = 110/200 = 55% Total % of Recessive Alleles Aa - 50 x 1 = 50 aa - 20 x 2 = 40 50 + 40 = 90 90/200 = 45%
BIO. B. 3 Theory of Evolution BIO. B. 3. 1. 2 Eligible Content Describe the factors that can contribute to the development of a new species (eg. isolating mechanisms, genetic drift, founder effect, migration)
Isolating Mechanisms Any factor that actively prevents breeding between organisms.
Genetic Drift • The random change in allele frequency in a population making traits more or less common • The process of change in the genetic composition of a population due to chance or random events rather than by natural selection, resulting in changes in allele frequencies over time • In each generation, some individuals may, by chance, leave behind more descendants than other individuals. The genes of the next generation will then be the result of the “lucky” individuals that survive, not necessarily the individuals who are naturally selected for their specific environment.
Genetic Drift
Founder Effect • The dramatic decrease in genetic diversity caused through the formation of a small colony of individuals that remained isolated. • A founder effect occurs when a new colony is started by a few members of the original population. This small population size means that the colony may have reduced genetic variation from the original population.
Founder Effect: For example, the Afrikaner population of Dutch settlers in South Africa is descended mainly from a few colonists. Today, the Afrikaner population has an unusually high frequency of the gene that causes Huntington’s disease, because those original Dutch colonists just happened to carry that gene with unusually high frequency. This effect is easy to recognize in genetic diseases, but of course, the frequencies of all sorts of genes are affected by founder events.
Migration • Any movement of individuals or populations from one location to another. • A periodic group movement of a species
BIO. B. 3 Theory of Evolution BIO. B. 3. 1. 3 Eligible Content Explain how genetic mutations may result in genotypic and phenotypic variations within a population.
Genetic Mutation • Random change in the DNA sequence of a gene • The only process that produces new alleles
Genotype • Mutations cause the genotypes of a population to change over time
Phenotype • As the genotype changes over time, the phenotype of a population can also change over time
Genetic Mutation The DNA in any cell can be altered through environmental exposure to certain chemicals, ultraviolet radiation or even errors that occur during the process of replication. Point mutations (missense, nonsense) or insertions, deletions and chromosomal mutations (deletion, duplication, inversion, translocation) can lead to genetic mutations. This changes the genotype which also could change the phenotype.
Genetic Mutation A missense mutation changes the sequence of the amino acids and can produce a new protein.
BIO. B. 3 Theory of Evolution BIO. B. 3. 2. 1 Eligible Content Interpret evidence supporting theory of evolution (ie. fossil, anatomical, physiological, embryological, biochemical and universal genetic code)
Fossil Evidence Fossils are traces of organisms that lived in the past. Comparing fossils and living beings reveals a pattern of gradual change from past to present.
Anatomical Evidence The anatomy or bodily structure of different species can be compared. Many internal similarities are evidence of how living things are related. Homologous structures are characteristics that are similar in two or more species and that have been inherited from a common ancestor of those species.
Embryological Evidence At some time during development, all vertebrates have a postanal tail and exhibit paired pharyngeal pouches supported by cartilaginous arches.
Biochemical All living things use the same biochemical molecules including DNA, RNA and ATP. The conclusion is that these molecules were present in the first living cell or cells and have been passes on as life began. Organisms use the same DNA triplet code and the same 20 amino acids in there protein. The number of amino acids in a sequence for a particular protein.
Universal Genetic Code The genetic code is universal to all living things. All living things share four common bases in DNA (A -T, C-G). And four common bases in m. RNA (A-U, C-G). All living things use these bases to undergo transcription and translation to produce proteins.
BIO. B. 3 Theory of Evolution BIO. B. 3. 3. 1 Eligible Content Distinguish between the scientific terms: hypothesis, inference, law, theory, principle, fact and observation.
Hypothesis A possible explanation that can be tested. A testable idea or explanation that leads to scientific investigation Examples: Left-handed people may have a higher IQ than right-handed people. If milk is poured in plants instead of water, then it will enhance their growth at a quicker rate.
Inference A conclusion made on the basis of facts and previous knowledge rather than on direct observation. An inference is not directly testable. An inference is the act of coming to a logical conclusion without actually witnessing or having first hand knowledge of an event Example: Everybody is wearing a rain coat, it must be raining. There is smoke coming from the kitchen, there must be a fire.
Law A statement based on repeated experimental observation that describes some aspect of the world Examples: Law of Gravity Newton’s Laws of Motion
Theory A system of ideas that explains many related observations and is supported by a large body of evidence acquired through scientific investigation. When a set of related hypotheses is confirmed to be true many times. Examples: Cell Theory of Evolution Quantum Theory
Principle A fundamental truth or proposition that serves as the foundation for a system of belief or behavior or for a chain of reasoning.
Fact An observation that has been confirmed repeatedly and is accepted as true.
Observation Obtaining knowledge by use of the five senses.
BIO. B. 4 Ecology BIO. B. 4. 1. 1 Eligible Content Describe the levels of ecological organization (ie. organism, population, community, ecosystem, biome, biosphere)
Organism An individual living thing.
Population All of the same species in the same place at the same time.
Community Groups of various species living together and interacting with one another.
Ecosystem All of the living and nonliving things that a species needs to survive in an area.
Biome Large regions of smaller ecosystems characterized by a specific climate and certain types of plants and animals.
Biosphere The area of Earth where life can exist. The part of the Earth's crust, waters, and atmosphere that supports life.
BIO. B. 4 Ecology BIO. B. 4. 1. 1 Eligible Content Describe the characteristic biotic and abiotic components of aquatic and terrestrial ecosystems.
Biotic Factors • Living or once living parts of an ecosystem
Abiotic Factors • Non-living factors of an ecosystem
Aquatic Ecosystem Abiotic Factors: Water Oxygen Carbon Dioxide Sediment Rocks Sunlight Biotic Factors: Animals Plants Algae Protozoans Decomposers (bacteria & fungi)
Terrestrial Ecosystem Abiotic Factors: Sunlight Oxygen Carbon Dioxide Soil Rocks Wind Biotic Factors: Living Animals Living Plants Bacteria Decomposers
BIO. B. 4 Ecology BIO. B. 4. 1. 1 Eligible Content Describe how energy flows through an ecosystem (eg. food chains, food webs, energy pyramid)
• All living things require a constant supply of energy • Any time one organism eats another organism, energy is transferred • This transfer of energy can be shown in a food chain, food web or energy pyramid • The levels in a food chain, food web or energy pyramid are known as trophic levels • A food chain can only have 4 or 5 trophic levels because there is not enough energy to sustain any more organisms • For the same reason, the population of organisms in higher trophic levels are smaller in number
Food Chain A feeding hierarchy in which organisms in an ecosystem are grouped into trophic (nutritional) levels and are shown in a succession to represent the flow of food energy and the feeding relationships between them. Energy flows from one trophic level to the next in a food chain The first trophic level is made up of producers The 2 nd level is made of herbivores (organisms that eat plants) The arrows indicate the flow of energy
Food Web Shows all of the possible feeding relationships in an ecosystem
Energy Pyramid
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