Chapter 3- Genetics- Theoretical Genetics Flashcards

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0
Q

Define phenotype

A

Characteristics of traits of an organisms

Eg: five fingers, colour blindness and type O blood

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1
Q

Define genotype

A

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

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2
Q

Define dominant allele

A

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

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3
Q

Define recessive allele

A

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

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4
Q

Define co dominant allele

A

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

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5
Q

Define locus

A

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

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6
Q

Define homozygous

A

Having 2 identical alleles of a gene

Eg: AA

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7
Q

Define heterozygous

A

Having 2 different alleles of a gene

Eg: Aa

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8
Q

Define carrier

A

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

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9
Q

Define test cross

A

Testing a suspected heterozygous by crosses it with a homozygous recessive

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10
Q

Do a diagram of a punnet grid

A

Martha.

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11
Q

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

A

ABO blood group system in humans

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12
Q

How does the ABO work as 3 alleles?

A

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

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13
Q

What do ABO blood types demonstrate ?

A

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

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14
Q

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

A

A, B, AB and O

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15
Q

How to ABO create these 4 blood types?

A

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

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16
Q

What is the gene for ABO blood type represented as?

A

Letter I

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17
Q

What is the allele for type A blood group?

A

I^A

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18
Q

What is the allele for type B blood group?

A

I ^ B

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19
Q

What is the allele for type O

A

ii

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20
Q

Crossing over of the ABO gives how many possibilities?

A

6

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21
Q

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

A

Gives phenotype blood group A

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22
Q

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

A

Blood group B

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23
Q

What does I^A I^B give?

A

Type AB

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24
Q

What does ii give in blood groups?

A

Blood group O

25
Q

Antigen A has what type of antibodies?

And what type of blood can’t it have/have?

A

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

26
Q

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

A

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

27
Q

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

A

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

28
Q

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

A

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

29
Q

How many pairs of chromosomes do humans have?

A

23

30
Q

What are the first 22 chromosomes known as?

A

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

31
Q

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

A

Heterosomes (sex chromosome) and determines gender

32
Q

What is the father always responsible for?

A

Determining gender

33
Q

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

A

A girl

34
Q

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

A

That is will be a boy or a girl

35
Q

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

A

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

36
Q

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

A

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

37
Q

Define sex linkage

A

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

38
Q

What are colour blindness and haemophilia both examples of?

A

X-linked recessive condiitions

39
Q

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

A

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

40
Q

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

A

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

41
Q

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

A

Higher frequency of being recessive and expressing trait

42
Q

Where do males inherit X linked recessive conditions from?

A

The mother

43
Q

Where do females inherit sex linked conditions from?

A

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

44
Q

What is the genotype for affect and unaffected haemophilia?

A

X^H= unaffected X^h=affected

45
Q

What is the genotype for affected and unaffected colour blindness

A

X^A=unaffected X^a=affected

46
Q

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

A

Fucking do it

47
Q

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

A

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
Q

Why can men only be hemizygous?

A

Only have 1 X chromosome (therefore only 1 allele)

49
Q

Why can females be carriers for X linked recessive conditions?

A

Because they have 2 chromosomes– males X Y can’t

50
Q

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

A

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

51
Q

Draw a punnet grid to show autosomal dominance/recessive

A

Jf kana

52
Q

Draw a punnet grid to show co dominance

A
53
Q

Draw a punnet grid to show x-linked recessive

A
54
Q

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

A

Unaffected- white circle

Affected- black circle

55
Q

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

A
Affected= black square 
Unaffected= white square
56
Q

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

A

At least one affected parent

57
Q

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

A

All must be unaffected

58
Q

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

A

May have offspring who are affected if parents are heterozygous

59
Q

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

A

Baka

60
Q

Draw a pedigree chart with a recessive allele as parents

A

Kahslanipasbbshdsk