When and where (in what part of a cell) do mutations occur?
-part of the cell: DNA
-happens in every living thing
What does it mean to say a
... [Show More] mutation is neutral, deleterious, or beneficial? Which of these is most common?
-neutral: no effect on fitness
-deleterious: reduces fitness
-beneficial: fitness increases
What is the difference between the effects of mutations in coding vs. non-coding regions?
coding sequence: sometimes changes amino acid sequence, sometimes not
What does it mean to say that a mutation is synonymous or nonsynonymous?
-synonymous: does not change amino acid
Why do we call an insertion or deletion an "indel"?
because you know that the alleles are different, but not sure how
How can you tell the difference between a missense and a nonsense mutation?
missense changes amino acid, nonsense has a stop codon- causes for a shorter protein
What are some examples of organisms that reproduce asexually?
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What are some differences between sexual and asexual reproduction? How do these differences affect genetic variation in populations?
- asexual: one parent that produces genetically identical offspring
-sexual reproduction: two individuals combine genetic information and produce offspring that are genetically different from parents
- asexual: all females are having babies
sexual: only half the population is having babies
When in a life cycle do mitosis and meiosis occur? What is the result of meiosis?
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Why does meiosis only occur in cells that have at least 2n DNA content?
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How might two sister chromatids acquire different alleles of the same gene?
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How might two non-sister chromatids of the same homologous pair acquire different alleles of the same gene?
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What events occur in each part of meiosis?
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What key parts of meiosis do you need to know so you can trace the movement of genetic information between germ cells and gametes?
meiosis
If there are two rounds of cell division during meiosis, does that also mean DNA replication occurs twice?
no, DNA replication occurs once
What is the ploidy of the cells undergoing meiosis after meiosis I and after meiosis II, assuming we start with a diploid germ cell?
4 haploid daughter cells
What are the 3 key places where genetic variation increases during meiosis? How much variation is gained by each of these?
1) maternal and paternal chromosomes recombine during meiosis
2) homologous chromosomes assort independently
3) male and female gametes combine randomly at fertilization
- variation #1: 1-3 per chromosome, variation
- #2: 8 million different combinations,
- variation #3: 70 trillion unique zygotes
In independent assortment, describe what is assorting independently. If a germ cell with 2n = 4 undergoes meiosis, how many unique gametes will result, assuming no mutations occur?
16
How does meiosis differ from mitosis? How are the two processes similar?
different:
-Mitosis produces 2 genetically identical daughter cells, occurs in somatic
-Meiosis produces four daughter cells, only in germ cells
Similar:
- DNA replication
-pulling apart of sister chromatids
How does a frameshift differ from an indel of 3 nucleotides? In your answer, include both differences in the process & the result of the mutation.
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How does reciprocal translocation differfrom crossing over during meiosis I?
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Which terms fall under the main category of "point mutations", and which fall under the category "chromosomal mutations"
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What information can you learn from looking at a karyotype?
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What occurs during meiosisI or meiosis II to result in a gamete that has extra or missing chromosomes? What happens if that aneuploid gamete fuses with another gamete with the proper number of chromosomes?
-nondisjunction
- you en
How did Esther and Joshua Lederberg determine that mutations are not caused by the environment and do not occur in response to an organism's needs? Be sure you can describe the setup and results of this experiment.
they used an approach called stamp plating (you put fabric on original plate and stamp it on second). They looked at what happened to the colonies. Only two were able to grow with antibiotic. They then washed original plate with antibiotic and and bacteria remained. Showed them that some cells already have resistant mutations in them
How can a non-synonymous mutation in a non-coding region be beneficial?
it could produce more protein that increases fitness
-turns something on that makes it beneficial [Show Less]