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Flashcards in L.8 Genetics Deck (17)
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1
Q

What is a Chromosome?

A

a threadlike structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Contain genes in a linear sequence

2
Q

What are alleles?

A

Alleles are alternative forms of a gene.

Dominant alleles require only one copy to be expressed

Recessive alleles require two copies to be expressed.

3
Q

What is a genotype and what are the three different genotypes possible?

A

A genotype is the combination of alleles one has at a given genetic locus.

  1. Homozygous; same allele
  2. Heterozygous; two different alleles
  3. Hemizygous; only having one allele
4
Q

What is a phenotype?

A

The observable manifestation of a genotype

5
Q

What are the three different patterns of dominance?

A
  1. Complete Dominance; one allele takes over
  2. Codominance; both alleles are physically present (AB blood type)
  3. Incomplete Dominance; No dominant alleles, an intermediate phenotype (purple flower color)
6
Q

What is the difference between Penetrance and Expressivity?

A

Penetrance: is the poportion of a population with a given genotype who express the phenotype

Expressivity: referes to the varying/different phenotypic manifestation of a given genotype.

7
Q

What are Mendel’s first and second laws?

A

1st; (of segregation) an organism has two alleles for each gene, which segregate during anaphase I in miosis, resulting in gametes carrying only one allele for a trait.

2nd; (of independent assortment) states that the inheritance of one allele does not influence the probability of inheriting an allele for a different gene, in prophase I

Both increasing diversity in the offspring

8
Q

Support for DNA as genetic material came from different experiments, explain these.

  1. Griffith
  2. Avery-MacLeod-Mccarty
  3. Hershey-Chase
A
  1. Converting of non-virulent bacteria to virulent bacteri by exposure to hear killed virulent bacterial
  2. DNA degradation caused cessation of bacterial transformation.
  3. Radiolabled DNA could be found in bacteriophage infected bacteria
9
Q

What is a gene pool?

A

All of the alleles found in a given population

10
Q

What are mutations?

A

DNA mutations are permanent changes in the DNAsequence of a gene. Mutations range in their severity. Some damage the way a cell or whole organism functions, or even cause lethality, while others have no effect. Mutations also range in the amount of DNAaltered.

11
Q

Nucleotide mutations include two major types, which are?

A

Point mutations; substitution of one cucleotide for another

Framshift mutations; moving the 3 letter transcriptionla reading frame.

12
Q

What are the 3 types of point mutations?

A
  1. Silent; no effect on protein
  2. Missence ; one amino acid for another
  3. Monsense; sub a stop codon for an amino acid
13
Q

What are the two different FRameshift mutations?

A

Insertions and Deletions, bot result in a shift in the reading frame leading to changes doe all downstream amino acids.

14
Q

What are the 5 chromosomal mutations affecting whole segments of DNA?

A
  1. Deletion: large segment of DNA is lost.
  2. Duplication: Segment of DNAis copies multiple times.
  3. Inversion: Segment of DNA is reversed.
  4. Insertion: Segment of DNA is moved from one chromosome to another.
  5. Translocation: Segment of DNA is swapped with a segment of DNA from another chromosome (Flip/flop)
15
Q

What is genetic leakage?

A

Genetic leakage is a flow od genes between species through hybrid offspring

16
Q

What is genetic drift?

A

Occurs when the composition of the gene pool changes as a result of chance.

Variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.

17
Q

Use founder effect, bottlenecks and inbreeding in the same sentence.

A

The founder effect results from bottlenecks that suddenly isolate a small population leading to inbreeding and increased prevalence of certain homozygous genotypes.