Unit 5 AP BIO exam review
Besides genetics, what environmental factors influence height and weight in humans?
nutrition, exercise, stress
Consider this Karyotype. Circle the chromosome abnormality.
there is 2 X chromosomes
If Huntington's disease was in your family, would you want to take the test to know if you had it for sure or not? Explain your thoughts
yes because it would effect my decision to have children
Some conservationists are concerned that climate change will decrease populations of reptiles. Why might this happen?
because as the temperatures get warmer with global warming more females will be born leading to a decrease in male population used reproduce.
Look at the pedigree on the right. Which trait is dominant (shaded or unshaded)? __________ What is the genotype of the male in generation 1? __________ What is the genotype of the first male in generation 2? ________ Of the second male in generation 2?_________
dom rr rr Rr or RR
There are trillions of times more possible genetic varieties of humans than than the number of people who have ever lived. Explain why genetic variety is so important to a species.
in evolution as it allows natural selection to increase or decrease frequency of alleles already in the population. ... Genetic variation is advantageous to a population because it enables some individuals to adapt to the environment while maintaining the survival of the population.
Sex-Linked Recessive Why is it rare to find a girl that is color blind?
low likelihood that a female would inherit 2 X allele vs a male is more likely to inherit it because it is a 50-50 chance of getting it.
From which parent do we inherit our mitochondrial DNA?
maternal
In your opinion, which of those four facts is the strongest piece of evidence for a common ancestor? Explain your reasoning.
molecular biology. I say this because it is the most concrete evidence you could get because it is looking a DNA and seeing how similar it it is genetically
Your mother passes away from sickle cell anemia, but your Father is normal. What is the chance that you have inherited the disease?
0 -50% depending on if the dad is homozygous dominate or heterozygous. if homo then no chance of getting it just a carrier. If hetero they have a 50% chance.
What is the percent recombination of the above cross? Show your work!
18 +15 divided by total number of offspring (445 +18+15+450) = 33/928 = 0.036 = 3.56%
A cell has 12 chromosomes (2n = 12). If this cell went through Meiosis, how many cells would there be: _________________ How many chromosomes in each? ___________
4 n= 6
If your father passes away from Huntington's disease, but your mother does not have the disease, what is the chance that you have inherited Huntington's?
50% because it is a dominate allele
Here is the percent recombination data for a set of four genes on the same chromosome. What is the most likely order of the genes? A - B 2% A - C 23% A - D 45% B - C 21% C - D 22%
A B C D
Read the four Essential Knowledge statements on the left (EVO 2.A.1-4). In your own words, explain how these facts can be used to support the theory that all life evolved from a common ancestor. Include: What traits must that common ancestor have had?
Anatomy: Species may share similar physical features because the feature was present in a common ancestor (homologous structures). Molecular biology: DNA and the genetic code reflect the shared ancestry of life. DNA comparisons can show how related species are. Biogeography: The global distribution of organisms and the unique features of island species reflect evolution and geological change. Fossils: Fossils document the existence of now-extinct past species that are related to present-day species. Direct observation: We can directly observe small-scale evolution in organisms with short lifecycles
TOPIC 5.3 Mendelian Genetics
ENDURING UNDERSTANDING EVO-2 Organisms are linked by lines of descent from common ancestry. LEARNING OBJECTIVE EVO-2.A Explain how shared, conserved, fundamental processes and features support the concept of common ancestry for all organisms. ESSENTIAL KNOWLEDGE EVO-2.A.1 DNA and RNA are carriers of genetic information. EVO-2.A.2 Ribosomes are found in all forms of life. EVO-2.A.3 Major features of the genetic code are shared by all modern living systems. EVO-2.A.4 Core metabolic pathways are conserved across all currently recognized domains. ENDURING UNDERSTANDING IST-1 Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.I Explain the inheritance of genes and traits as described by Mendel's laws. ESSENTIAL KNOWLEDGE IST-1.I.1 Mendel's laws of segregation and independent assortment can be applied to genes that are on different chromosomes. IST-1.I.2 Fertilization involves the fusion of two haploid gametes, restoring the diploid number of chromosomes and increasing genetic variation in populations by creating new combinations of alleles in the zygote— a. Rules of probability can be applied to analyze passage of single-gene traits from parent to offspring. b. The pattern of inheritance (monohybrid, dihybrid, sex-linked, and genetically linked genes) can often be predicted from data, including pedigree, that give the parent genotype/phenotype and the offspring genotypes/phenotypes.
TOPIC 5.1 Meiosis
ENDURING UNDERSTANDING IST-1 Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.F Explain how meiosis results in the transmission of chromosomes from one generation to the next. ESSENTIAL KNOWLEDGE IST-1.F.1 Meiosis is a process that ensures the formation of haploid gamete cells in sexually reproducing diploid organisms— a. Meiosis results in daughter cells with half the number of chromosomes of the parent cell. b. Meiosis involves two rounds of a sequential series of steps (meiosis I and meiosis II). LEARNING OBJECTIVE IST-1.G Describe similarities and/ or differences between the phases and outcomes of mitosis and meiosis. ESSENTIAL KNOWLEDGE IST-1.G.1 Mitosis and meiosis are similar in the way chromosomes segregate but differ in the number of cells produced and the genetic content of the daughter cells.
TOPIC 5.2 Meiosis and Genetic Diversity
ENDURING UNDERSTANDING IST-1 Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.H Explain how the process of meiosis generates genetic diversity ESSENTIAL KNOWLEDGE IST-1.H.1 Separation of the homologous chromosomes in meiosis I ensures that each gamete receives a haploid (1n) set of chromosomes that comprises both maternal and paternal chromosomes. IST-1.H.2 During meiosis I, homologous chromatids exchange genetic material via a process called "crossing over" (recombination), which increases genetic diversity among the resultant gametes. IST-1.H.3 Sexual reproduction in eukaryotes involving gamete formation—including crossing over, the random assortment of chromosomes during meiosis, and subsequent fertilization of gametes—serves to increase variation.
TOPIC 5.4 Non-Mendelian Genetics
ENDURING UNDERSTANDING IST-1 Heritable information provides for continuity of life. LEARNING OBJECTIVE IST-1.J Explain deviations from Mendel's model of the inheritance of traits. ESSENTIAL KNOWLEDGE IST-1.J.1 Patterns of inheritance of many traits do not follow ratios predicted by Mendel's laws and can be identified by quantitative analysis, where observed phenotypic ratios statistically differ from the predicted ratios— a. Genes that are adjacent and close to one another on the same chromosome may appear to be genetically linked; the probability that genetically linked genes will segregate as a unit can be used to calculate the map distance between them. IST-1.J.2 Some traits are determined by genes on sex chromosomes and are known as sexlinked traits. The pattern of inheritance of sex-linked traits can often be predicted from data, including pedigree, indicating the parent genotype/phenotype and the offspring genotypes/phenotypes. IST-1.J.3 Many traits are the product of multiple genes and/or physiological processes acting in combination; these traits therefore do not segregate in Mendelian patterns. IST-1.J.4 Some traits result from non-nuclear inheritance— a. Chloroplasts and mitochondria are randomly assorted to gametes and daughter cells; thus, traits determined by chloroplast and mitochondrial DNA do not follow simple Mendelian rules. b. In animals, mitochondria are transmitted by the egg and not by sperm; as such, traits determined by the mitochondrial DNA are maternally inherited. c. In plants, mitochondria and chloroplasts are transmitted in the ovule and not in the pollen; as such, mitochondria-determined and chloroplast-determined traits are maternally inherited.
TOPIC 5.5 Environmental Effects on Phenotype
ENDURING UNDERSTANDING SYI-3 Naturally occurring diversity among and between components within biological systems affects interactions with the environment. LEARNING OBJECTIVE SYI-3.B Explain how the same genotype can result in multiple phenotypes under different environmental conditions. ESSENTIAL KNOWLEDGE SYI-3.B.1 Environmental factors influence gene expression and can lead to phenotypic plasticity. Phenotypic plasticity occurs when individuals with the same genotype exhibit different phenotypes in different environment ILLUSTRATIVE EXAMPLES § Height and weight in humans § Flower color based on soil pH § Seasonal fur color in arctic animals § Sex determination in reptiles § Effect of increased UV on melanin production in animals § Presence of the opposite mating type on pheromone production in yeast and other fungi
TOPIC 5.6 Chromosomal Inheritance
ENDURING UNDERSTANDING SYI-3 Naturally occurring diversity among and between components within biological systems affects interactions with the environment. LEARNING OBJECTIVE SYI-3.C Explain how chromosomal inheritance generates genetic variation in sexual reproduction. ESSENTIAL KNOWLEDGE SYI-3.C.1 Segregation, independent assortment of chromosomes, and fertilization result in genetic variation in populations. SYI-3.C.2 The chromosomal basis of inheritance provides an understanding of the pattern of transmission of genes from parent to offspring. SYI-3.C.3 Certain human genetic disorders can be attributed to the inheritance of a single affected or mutated allele or specific chromosomal changes, such as nondisjunction. ILLUSTRATIVE EXAMPLES § Sickle cell anemia § Tay-Sachs disease § Huntington's disease § X-linked color blindness § Trisomy 21/Down syndrome
What causes "variety" in our mitochondrial DNA?
Mutations
What does 'haploid' mean (compared to diploid)?
Haploid cells contain only one set of Chromosomes (n). Diploid, as the name indicates, contains 2 sets of chromosomes (2n). Haploid cells are formed by the process of meiosis. Diploid cells undergo mitosis.
Hemophilia is a sex linked trait. Mary's father has hemophilia, but she does not. She marries a man who does not have hemophilia. What are the chances that she has a son with hemophilia? Make a punnett square to prove your answer!
If Mary's father has hemophilia, his X chromosome has the hemophilia gene, which he passed on to all his daughters (mary). Mary then is a carrier, and will pass her affected X fifty percent of the time. For her boys, this would be their only X, so they would have hemophilia.Overall the son has a 25% chance of having hemophilia
A particular mutation in a species of plant leads to variegation in its leaves (part of each leaf is white, while part is green). A plant breeder takes pollen from a green plant and pollinates a variegated plant. All resulting offspring are variegated. The breeder then takes pollen from a variegated plant and pollinates a green plant. All resulting offspring are green. What is going on?
In the first case the male plant is green and the female plant is variegated. Their progeny consists of only variegated plants. In the second case the male plant is variegated and the female plant is green. Their progeny consists of only green plants. It can be observed that the progeny always shows the leaf color phenotype of the female parent. This is a case of maternal inheritance. After fertilization, the embryo has mitochondria and chloroplast from the female parent. This happens because the male gamete is very small and devoid of any organelle whereas the female gamete is big and carries its organelles. Out of all the organelles in female gamete, mitochondria and chloroplast have their own DNA. Here, the gene for leaf color is probably located on chloroplast's DNA since it contains chlorophyll which is responsible for leaf color. If the female parent has green leaves, it will pass the gene for it to the next progeny as well via organellar DNA. This way the progeny will always have the same leaf color as the female parent.
In your own words, what are Mendel's Laws: Law of Segregation: Law of Independent Assortment:
Law of Segregation: states that a diploid organism passes a randomly selected allele for a trait to its offspring, such that the offspring receives one allele from each parent. Law of Independent Assortment: describes how different genes independently separate from one another when reproductive cells develop. ... During meiosis, the pairs of homologous chromosome are divided in half to form haploid cells, and this separation, or assortment, of homologous chromosomes is random.
Briefly describe what happens during each phase of meiosis: Meiosis I: Meiosis II:
Meiosis I: Meiosis 1 separates the pair of homologous chromosomes and reduces the diploid cell to haploid. It is divided into several stages that include, prophase, metaphase, anaphase and telophase Meiosis II: the sister chromatids within the two daughter cells separate, forming four new haploid gametes. The mechanics of meiosis II is similar to mitosis, except that each dividing cell has only one set of homologous chromosomes.
What are the primary similarities and differences between Mitosis and Meiosis?
Mitosis: 4 stages in total (plus interphase), happens in somatic cells, purpose is cellular prorefiration, produces 2 diploid daughter cells, chromosome # remain the same, genetic varaition does not change. Both: produce new cells, similar basic steps, start with single parent cell Meiosis: 8 stages in total, happens in germ cell, purpose of sexual reproduction, produes 4 haploid daughter cells, chromosme daughter is haved in each daughter cell, gentci varaition increased
Two yellow squash will always have yellow offspring. White squash will sometimes have white offspring, but sometimes yellow. Which trait is dominant?
White is dominant. Yellow plants (recessive) are homozygous, so they would always have homozygous recessive yellow offspring. White plants could be homozygous or heterozygous. 2 heterozygous yellow squash could have white offspring.
White flower color is recessive to purple flower color in pea plants. A white pea plant is crossed with a purple pea plant, yielding 554 white offspring and 568 purple offspring. What are the genotypes of each parent?
White is recessive, so it must be homozygous recessive. Purple is dominant, the purple plant could be homozygous dominant or heterozygous. If the purple parent were homozygous, all of the offspring would be purple. Since they were half purple and half white, the purple plant must be heterozygous.
Using the graph, fill in the words 'chicks' and 'dudes' in the right blanks. Sex determination in reptiles is controlled by temperature, you get hot ________and cool _________
chicks ---> dudes
Non-nuclear Inheritance: Besides the nucleus, where else can DNA be found in cells (think plants and animals)?
chloroplast and mitochondria
For some animals, an increase in the melatonin hormone triggers the melanin gene to turn off. What stimulates your brain to make melatonin? How does this explain why these arctic animals turn white in the winter?
darkness durin the winter there is less sunlight --> leds to the animal becoming whiter during winter.
This is a result of ______________ during meiosis. What part of meiosis failed (explain what happened)?
nondisconjunction. supposed to happen during anaphase 1 (where homologous pairs are pulled apart) and anaphase 2 (where sister chromatids are pulled apart)
The color of the Hydrangea varies based on what change in the environment? _________
pH
Multiple Genes: If there is ever one trait that can have more than three possible phenotypes, it must be due to ______________ genes. List three examples:
polymorphic Two human examples of multiple-allele genes are the gene of the ABO blood group system and the human-leukocyte-associated antigen (HLA) genes.
What environmental factor influences human melanin expression? HINT consider what you must do to get a tan.
sun exposer
What is a P Cross?
the inital crossing between the parent generation
What is a F1 cross?
the kids of the P generation... 1st generation F1 (first filial) generation - P offspring
Short stems are recessive to long stems, and white is recessive to purple.. You cross a white short plant with a heterozygous purple long plant, The offspring are 445 white short 18 white long 15 purple short 450 purple long Which of Mendel's Laws is being broken? Why is this happening?
the law of independent assortment is being broken. the offspring should be in a 1:1:1:1 ratio, but they are not. This means these 2 traits must be on the same chromosome, and only when crossing over happens will the alleles separate
In fruit flies, white eyes is sex-linked recessive. A white eye female mates with a wild type male. Make a punnett square showing the ratio of their male vs female offspring. The pedigree is of a sex linked recessive trait. Fill in the genotype for each individual.
there is a 50% chance that it would be a girl or boy if girl it is likly to be wild type while if it is a guy it is likely to be white eyed
Why is this response (to make more melanin) an adaptive advantage? What does melanin do for us?
this is advantage because the melanin blocks the sunlight UV rays from damaging our DNA.
What is the purpose of Meiosis?
to produce gametes, the sperm and eggs, with half of the genetic complement of the parent cells.