Chromosomal Basis of Inheritance

Question 1

Define: Transmission Genetics

Answer 1

How gene are inherited by following the products of gene expression in the form of characteristics.

Question 2

Define: Gene

Answer 2

The dsDNA sequence that codes for RNA/Protein. Includes non-coding control elements (Promoters).
- Considered the “units” of inheritance

Question 3

What sis the central dogma?

Answer 3

DNA(gene)–> mRNA –> Protein

Question 4

Define: Chromosomes

Answer 4

Long dsDNA molecule containing different genes
- 22 pairs of autosomes (2 copies of every gene), 1 pair sex chromosomes
-Imaged in a karyotype

Question 5

Define: Haploid

Answer 5

Containing 1 copy of every gene
- Prokaryotic cells

Question 6

Explain: Meiosis

Answer 6

Two cell divisions in germ cells to produce gametes
-prophase, metaphase, anaphase, and telophase
-Genetic diversity!
-Haploid

Question 7

Explain: Mitosis

Answer 7

One cell divisions in somatic cells to produce two identical daughter cells during growth and repair
- Diploid

Question 8

Describe how meiosis ensures genetic diversity

Answer 8

1. Crossing over: An exchange of DNA between homologous chromosomes in prophase 1.
2. Independent assortment: Arrangement of sister chromatids at the equatorial plane in metaphase is random

Question 9

Define: Genotype

Answer 9

Genetic composition (alleles/genes) of an organism

Question 10

Define: Phenotype

Answer 10

Detectable manifestation of a gene (Visible/physical)

Question 11

Define: Wild type

Answer 11

Natural or standard lab form of a genotype or phenotype for a particular organism

Question 12

Define: Allele

Answer 12

Different versions of the same gene (Diploid= 2 alleles)

Question 13

Define: Mutation

Answer 13

A difference in the nucleotide sequence difference from the wild type.

Question 14

Define: Homozygous

Answer 14

Diploid containing identical alleles for a gene

Question 15

Define: Heterozygous

Answer 15

Diploid containing different alleles for a gene

Question 16

Describe: Dominant

Answer 16

Phenotype expressed from one of the alleles in a heterozygote.

Question 17

Describe: Recessive

Answer 17

Phenotype that is not expressed from one allele in a heterozygote. Phenotype is only observed in homozygous recessive progeny

Question 18

Describe: Monohybrid Cross

Answer 18

A cross between 2 organisms that are both heterozygous for a sing trait being followed
- Could also be a dihybrid or trihybrid cross

Question 19

Describe how to identify a dominant and recessive allele

Answer 19

1) Homo. dominant (+/+) crossed with homo. recessive (-/-) will yield all dominant allele phenotype (+/-)

2) Heter. dominant (+/-) crossed with heter. dominant (+/-) will yeild a 3:1 ratio for dominant allele phenotype.
- also used to determine heterozygotes

Question 20

Describe: Test cross

Answer 20

Cross of an organism with a heterozygous dominant (+/-) phenotype, and a homozygous recessive phenotype.
- Will yield a 1:1 ratio

Question 21

Describe: Mendels Laws

Answer 21

1. Equal segregation: Two copies of a gene separate so that the gametes each have one allele. Each gamete has the same chance of receiving either.
2. Independent assortment: Segregation of a pair of alleles for 1 gene is independent of segregation of alleles for another (Metaphase 1)

Question 22

X^2 Test

Answer 22

Just know it bro

Question 23

What are the ratios you would expect from a monohybrid, dihybrid, and trihybrid cross respectively?

Answer 23

Monohybrid–> 3:1
Dihybrid –> 9:3:3:1
Trihybrid –> 27:9:9:9:3:3:3:1