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Flashcards in Inheritance Deck (46)
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1

Who created the concept of inheritance?

Gregor Mendel

2

What did Gregor Mendel study?

Peas

3

What did Gregor Mendel find in his studies?

That some traits are recessive and some are dominant

4

Define phenotype

A physical characteristic of an organism, which is determined by the organisms genotype as well as the environment.

5

Define genotype

A set of alleles possed for a particular gene or genes of an organism

6

When doing testing for inheritance what is good features and factors to have of the trial?

-Breed often and have lots of offspring
-Observable phenotypes
-Short lifecycle
-Produce statistically significant results

7

Define homozygous

If an individual contains two alleles that are coding for the same dominant or recessive trait (also known as pure breeding)

8

Define heterzygous

Individuals with one allele coding for the recessive trait and one allele coding for the dominant trait. Also known as hybrids)

9

What is complete dominance?

When a phenotype trait is completely dominant over the other trait

10

Why does complete dominance occur?

Enough protein being produced from a single allele for a particular phenotype, or two alleles coding for a dominant trait.

11

Define Dominant Trait

A trait that is expressed with a heterozygous genotype. Only a single copy of the allele is required for the traits expression

12

Deine Recessive Trait

Refers to a trait that is only expressed in a homozygous genotype.

13

Define Pure Breeding

An organism that contains two exact alleles and when crossed with it self or others like t, it will always produce an offspring with a phenotype the same.

14

Define Codominance

When both alleles in the genotype are expressed equally in the phenotype, resulting in both traits being exhibited

15

Define Incomplete Dominance

Two pure breeding parents that can have an offspring that have a blend of their parental phenotype

16

Define Dihybrid crosses

When two genes are crossed they can either be on the same chromosome or different

17

What will the test cross for a heterozygous individual result in reagrds to the ratio

1:1:1:1

18

When are alleles considered to be linked?

When they are on the same chromosome

19

Define alleles

Alternative forms of a gene

20

Define Chromosomes

Strand of DNA encoded of genes

21

Define Autosomal Recessive

A genetic condition that appears only in individuals who have recieved two copies of an autosomal gene, one from each parent

22

Define Autosomal Dominant

Requires only one of the affected trait in the genotype for it to be expressed in the phenotype

23

Define a gene

Short section of DNA that codes for a specific protein

24

Where are genes located?

Chromosomes

25

what do alleles code for?

traits

26

Define chromosome

One long DNA molecule surrounded by many histone proteins

27

Why are DNA supercoiled chromatin?

In order to fit within a cell

28

Why is the centromere important?

Helps anchor the chromosome to spindle fibres during the cell division process of miitosis and meiosis.

29

Define autosomal chromosomes

Form homologous pairs that do not differ between sexes

30

Define sex chromosomes

Determine the sex of an organism

31

Define somatic cells

They are body cells

32

What are egg or sperm cells?

Haploid

33

What are somatic cells?

Diploidd

34

Define hemizygous

One gene is deleted

35

What are lethal genotypes

In some cases homozygous genotypes can be lethal,
will produce a ratio of 2:1
will be double dominant

36

Define pedigree

A family tree that shows the frequency and occurence of a particular phenotype over many generations

37

what is polygenetic inheritance

Chracteristic is controlled by more than one gene

38

What variation are polygenic inhertiance

Continous varitation

39

Discontinous Variation

When members of a population can be grouped into a few discrete and non-overlapping classes of a trait

40

what is discontinous variation caused by?

A single gene monogenic

41

Continous variation

characteristics which exhibit a continous range of phenotypes across a population

42

what is continous variation caused by?

polygenes

43

What are charactersitics of an autosomal dominant pedigree?

-Both males and females can equally be affected
-No gender bias
-everyone will have an effected parent

44

What are charactersitics of an autosomal recessive pedigree?

-both males and females will be equally affected
-can skip a generation

45

Pedigree: X linked dominant

An affected male will pass the trait to all his daughters
Affected person has at least one affected parent

46

X linked recessive pedigree

Father of affected female must show trait