Genetics Flashcards Preview

Biology > Genetics > Flashcards

Flashcards in Genetics Deck (64)
Loading flashcards...
1

What is sexual reproduction

Reproduction involving fertilisation of a female sex cell by a male sex cell

2

What is asexual reproduction

Reproducing without fertilisation

3

What does asexual reproduction produce

It produces clones

4

What are clones

Offspring that are genetically identical to the parent

5

How do plants produces asexually

Some use runners and some use bits of plants or roots

6

How do runners help plants produce asexually

The runner supplies the daughter plant with water and nutrients until its roots and leaves are developed
The daughter plant grows in a node where the runner touches the grounds

7

What does sexual reproduction produce

Produces offspring that are different from each other

8

When in sexual reproduction an advantage

If the offspring move to an area with different environmental conditions or if the environment changes

9

What does variation mean

That there is a greater chance that some offspring will be better suited to new conditions and so will be more likely to survive and reproduce

10

When is asexual reproduction an advantage

When there are lots of resources such as food

11

What is DNA

Where an organisms instructions are found as code

12

What is a humans genome

All the DNA of an organism

13

Where is the human genome found

On 46 long molecules of DNA and each molecule is inside a chromosome

14

What is a chromosome

A thread like structure found in the nuclei of cells. Each chromosome contains one long DNA molecule packed with proteins

15

What is found along the length of a DNA molecule

Sections that each contain a code for making a protein called genes

16

What is a gene

A sexton of a long strand of DNA found in a chromosome that often contains instructions for a specific protein

17

What is controlled by genes

The order of amino acids

18

How many genes do human have

20000

19

What is a diploid cell

A cell or nucleus that contains 2 sets of chromosomes (2N)

20

Why do gametes need to be haploid

So they just have one set of chromosomes instead of diploid where they would have 4 sets

21

What is a haploid cell

A cell or nucleus that contains 1 set of chromoso,es (1N)

22

What does mitosis produces

Diploid and plants and body cells
Needed for growth and repair
Divides once
2 cells produced
Genetically identical cells

23

What does meiosis produce

Haploid cells and gametes
Ended for producing sex cells
Divides twice
Four cells produced
Genetically different cells

24

What happens during meiosis

Each chromosome replicates and the two copies remain attached to make each chromosome look like and X
The 2 sets of chromosomes pair up forming 23 pairs
The pairs then separate into two new cells
The two copies of a chromosome in each X shape split into two new cells

25

How is a double helix formed

A molecule of DNA contains two strands which form a helix
The two strands are joined together by bases to form a double helix

26

What are the 4 DNA bases

Adenine, thiamine, cytosine, guanine

27

DNA bases pairings

A pairs with T
C Pairs with G

28

What does a nucleotide consist of

Each base is attached to a sugar called deoxyribose
The sugar is attached to a phosphate group

29

What are the weak forces of attraction between bases

Weak hydrogen bonds

30

How many bonds do c and g form


How many bonds do a and t form

C and g form 3 hydrogen bonds

A and t form 2

31

What is a mutation

A change in the bases of a gene

32

When is a mutation caused

When DNA is not copied properly in cell division or environmental factors

33

What is an allele

Different form of the same gene

34

What is a polypeptide chain

A chain of amino acids

35

What happens if you change the order of the DNA nucleotides

The complementary sequence of amino acids will alter

36

Example of a mutation in coding DNA

Sick
E cell anemia

37

What happens in mutatupions in non coding DNA

RNA polymerase attaches to DNA bases in front of a gene and may result in the RNA polymerase not binding well reducing transcription
Or RNA polymerase binding better and poducing more mRNA

38

Example of mutations in non coding DNA

B thalassaemia in which not enough b polypeptide is made for haemoglobin. Causes tiredness weakness and shortness of breath

39

When is an organism heterozygous

If the alleles are different

40

When is an organism homozygous

If both allege for one gene are the same

41

When is a gene dominant

When it has an affect

42

When is an gene recessive

When it has no affect

43

When is recessive characteristic seen

If both alleles are recessive

44

What is an organisms genotype

The alleles in an organism

45

What is an organisms phenotype

What the organism looks like

46

What is a mono hybrid cross

When it is RW

47

What results in codominance

Monohybrid crosses. That both alleles are expressed at the same time and results in the blending of the final phenotype

48

What chromosomes do females have


What chromosomes do men have

Females have two X chromosomes


Males have one X and one Y

49

What is a family pedigree chart used for

Shows haw genotype sand their resulting phenotypes are inherited in families

50

Blog groups in the ABO blood group system

A,B,AB,O

51

Allene of the ABO blood groups

I^A, I^B, I^O

52

What is codominance

When both alleles for a gene affect the phenotype

53

Dominance and recessive in ABO blood group

I^A and I^B are both dominant to I^O but I^A and I^B are condomiant
I^O is recessive

54

Genotype of A
AB

B

O

A: I^A I^A, I^A I^O

AB: I^A I^B, I^B I^A

B: I^B I^B, I^B I^O

O: I^O I^O

55

If an inherited disorder is locates on the section of the X chromosome that is missing on the Y chromosome then why will a male inherit the trait

Because in humans the Y sex chromosome is disctinctly shorter than the X and there fore is missing a number of genes

56

What would happen if a woman inherits the disorder allelewhat would happen

She may have a healthy allele on her other X chromosome. If the alllele is recessive she won't inherit it. If both alleles are recessive she will develop the disorder

57

What does it mean if a parent is a carrier of the disorder allele

They have one faulty allel and one normal allele

58

What gene affects eye colour

0CA2 that controlles the melanin produced

59

When do mutation happen

When there is a mistake in coping DNA ditching cell division. One base in a DNA sequence might be replaced by another

60

What did the hGP do

Produced a map of 3.3 billion complementary base pairs in one set of 46 chromosomes. The first complete human genome was decoded

61

Why is mapping a persons genome done

Can indicate their risk of developing disease that are caused by different alleles of genes. Also identify which medicines might be best to treat a persons illnes because the alleles we have can affect how medicines work in the body

62

HT happens in haemophilia

Sex linked heridtoy genetci condition. Patients can't make one of three types of blood clotting chemicals.
Without it an incomplete playlet will plug will form In the wound and blood will be lost
Type A is most common and severe as factor 8 isn't produced

63

What happens in point mutation

A nuclei ide is gone so another is substituted and deleted

64

What the possible phenotypic outcomes of mutation

No change to phenotype

Small change to phenotype

Large change to phenotype