Genetics Flashcards Preview

Biology > Genetics > Flashcards

Flashcards in Genetics Deck (28):
0

Gene def

Genetic material coding for a single gene product (peptide, rRNA or tRNA)

1

Locus def

The chromosomal location of a gene

2

Allele def

One variant of a gene

3

Homologous chromosomes def

Chromosomes that code for the same set of genes
-may have different alleles
-one recieved from each parent

Ex) both chromosomes have hair color on their gene
One may have blonde one may have brown

4

Genotype vs phenotype
B=brown
B=blue

Genotype: BB
Phenotype: brown

5

Law of segregation

Separation of alleles in the haploid gametes
-the two alleles for a gene separate into our gametes

6

Law of independent assortment

Genes assort independently into the progeny

7

Complete dominance

When a heterozygote has the phenotype of only one of the alleles (the dominant one)

8

Incomplete dominance

Phenotypes of the dominance are blends of the parental phenotypes

9

Codominance

Both inherited alleles are completely expressed

10

YyRr x YyRr

Y_R_ 9
Y_rr 3
yyR_ 3
Yyrr 1

11

Test cross

Determines a genotype
-cross with a homozygous recessive

12

Pleiotropism

When a gene has multiple phenotypes associated with its expression

13

Polygenism

Multiple genes affect a single trait

14

Penetrance

Probability an organism with a specific genotype will express a particular phenotype

15

Expressivity

Term describing the variation of phenotype for a specific genotype

16

Epistasis

Occurs when the expression of a gene is dependent upon another gene
-expression of red hair is dependent on whether you have hair

17

Out of the 46 chromosomes, which are linked to our gender

2 x and y chromosomes
All orher 44 chromosomes are called the autosomes

18

If you are a female what are your chromosomes
Male?

Female: xx
Male: xy

19

Who determines the sex of the offspring?

The male
-the female always provides an x
-it is up to the male whether he provides an x or y

20

X or y chromosome larger

X-has many genes
Y-is very small, not many genes

21

Turner syndrome

Child only has an x chromosome
-ends up a female
-from nondisjunction

22

Kleinfelter syndrome

Child has three sex chromosome
-xxy
-develop as a male
-from nomdisjunction

23

Point mutation

Substitution, insertion, deletion
-change of a single nucleotide

24

Missense mutation

Point mutation leading to a codon coding for a different amino acid
-may or may not have a big affect on the protein

25

Point mutation that has no consequence

Point mutation in the third position of the codon

26

Nonsense mutation

Point mutation that leads to a premature stop codon

27

Frame-shift mutations

Insertion or deletion lesding to a change in the reading frame of a gene