Chapter 3- Genetics- Theoretical Genetics Flashcards Preview

Biology > Chapter 3- Genetics- Theoretical Genetics > Flashcards

Flashcards in Chapter 3- Genetics- Theoretical Genetics Deck (61):
0

Define genotype

Symbolic representation of a pair of alleles possessed by an organism
eg: Bb GG tt

1

Define phenotype

Characteristics of traits of an organisms
Eg: five fingers, colour blindness and type O blood

2

Define dominant allele

Always expressed when its present it cannot be masked by a normal allele

3

Define recessive allele

Can be masked by another allele- only expressed when 2 copies are present

4

Define co dominant allele

Pairs of alleles that both have affect on the phenotype when present on a heterozygous

5

Define locus

Particular position on homologous chromosomes of a gene. Each gene is found on a specific pair of chromosomes

6

Define homozygous

Having 2 identical alleles of a gene
Eg: AA

7

Define heterozygous

Having 2 different alleles of a gene
Eg: Aa

8

Define carrier

An individual that has one copy of a recessive allele that causes a genetic disease in individuals that are homozygous for this alleles

9

Define test cross

Testing a suspected heterozygous by crosses it with a homozygous recessive

10

Do a diagram of a punnet grid

Martha.

11

What is an example of genes that have more that 2 alleles?

ABO blood group system in humans

12

How does the ABO work as 3 alleles?

Share co-dominance (can be expressed equally in phenotype) and share incomplete dominance (neither fully expressed phenotype=blending)

13

What do ABO blood types demonstrate ?

A dominance order (allele A > allele B > allele C)

14

What are the four possible phenotype types for ABO blood groups?

A, B, AB and O

15

How to ABO create these 4 blood types?

There are 3 alleles of the gene and these alleles can produce 6 different genotypes

16

What is the gene for ABO blood type represented as?

Letter I

17

What is the allele for type A blood group?

I^A

18

What is the allele for type B blood group?

I ^ B

19

What is the allele for type O

ii

20

Crossing over of the ABO gives how many possibilities?

6

21

What does I^A I^A or I^A i give?

Gives phenotype blood group A

22

What does I^B I^B or I^B i give?

Blood group B

23

What does I^A I^B give?

Type AB

24

What does ii give in blood groups?

Blood group O

25

Antigen A has what type of antibodies?
And what type of blood can't it have/have?

Anti-B antibodies and can't have B or AB blood but can have O or A blood

26

Antigen B what type of antibodies does it have? And what type of blood can it have/can't have

Has anti-A antibodies and can't have A or AB blood but can have B or O blood

27

What type of antibodies does antigen AB have? And type of blood can it have/can't have

Doesn't have any antibodies but can have any blood type- it is the universal recipient

28

What types of antibodies has A and B?and what types of blood can it only have?

Has both A and B antibodies and can only have O blood- is the universal donor

29

How many pairs of chromosomes do humans have?

23

30

What are the first 22 chromosomes known as?

Autosomes- each chromosome pairs possess the same genes and structural features

31

What is the 23rd chromosome responsible for and known as?

Heterosomes (sex chromosome) and determines gender

32

What is the father always responsible for?

Determining gender

33

If male sperm contains X chromosome the embryo will defiently be?

A girl

34

There is always a 50\50% chance on what? Also draw the grid to prove it

That is will be a boy or a girl

35

A Y chromate is different in size to an X chromosome how?

It is much smaller and only contains a few genes- has fewer loci

36

On males where are the majority of alleles present? And what does this impact?

On the X chromosome and have no alleles to pair with on the smaller Y chromosome

37

Define sex linkage

Any genetic trait whose allele has its locus on the X chromosome is sex linked

38

What are colour blindness and haemophilia both examples of?

X-linked recessive condiitions

39

Where is the gene loci found for colour blindness/haemophilia on the X chromosome?

On the non-homologous region of the X chromosome (not present in Y chromosome)

40

Why can't males carry the gene for colour blind embeds and haemophilia?

As males only have one allele for this gene they cannot carry it for the condition

41

As males can't carry the gene for haemophilia and colour blindness what does this mean they have a higher frequency of?

Higher frequency of being recessive and expressing trait

42

Where do males inherit X linked recessive conditions from?

The mother

43

Where do females inherit sex linked conditions from?

Females only inherit an X linked condition if they receive a recessive gene from both parents

44

What is the genotype for affect and unaffected haemophilia?

X^H= unaffected X^h=affected

45

What is the genotype for affected and unaffected colour blindness

X^A=unaffected X^a=affected

46

Draw a punnet grid to show how males and females inherit colour blindness and haemophilia

Fucking do it

47

Why can females be homozygous or heterozygous with respect to sex linked genes?

As human females have 2 X chromosomes (and therefore 2 alleles for any give X-linked gene) they can be either homozygous or heterozygous

48

Why can men only be hemizygous?

Only have 1 X chromosome (therefore only 1 allele)

49

Why can females be carriers for X linked recessive conditions?

Because they have 2 chromosomes-- males X Y can't

50

So why does a male have a greater chance of getting a sex linked condition?

Cuz a male only inherits an X chromosome from his mother not his father.

51

Draw a punnet grid to show autosomal dominance/recessive

Jf kana

52

Draw a punnet grid to show co dominance

53

Draw a punnet grid to show x-linked recessive

54

On a pedigree chart what represents an unaffected female and an affected female

Unaffected- white circle
Affected- black circle

55

On a pedigree chart what represents an Unaffected male and an affected male?

Affected= black square
Unaffected= white square

56

All affected individuals must have at what on a pedigree chart?

At least one affected parent

57

If 2 parents are unaffected on a pedigree chart what are the offspring?

All must be unaffected

58

If 2 parents are affected on a pedigree chart what are the offspring?


May have offspring who are affected if parents are heterozygous

59

Draw a diagram of a pedigree chart with a dominant allele as parents

Baka

60

Draw a pedigree chart with a recessive allele as parents

Kahslanipasbbshdsk

Decks in Biology Class (64):