genetics Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

what is sexual reproduction

A

where genetic information from 2 organisms is combined to produce offspring which are genetically different to either parent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

what is a gamete

A

reproductive cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

examples of reproductive cells

A

sperm
egg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

what is a haploid cell

A

half the number of chromosomes in the normal cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

examples of diploid cells

A

gametes (sperm and eggs)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

what happens during fertilisation

A

a male gamete fuse with a female gamete to produce a fertilised egg, also known as a zigote. The zygote sperm ends up with the full set of chromosomes (so it is diploid).

The embryo inherits characteristics from both parents, as it has received a mixture of chromosomes (and therefore genes) from its mum and its dad.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a zygote

A

female gamete which produces a fertilised egg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

how are gametes produced

A

meiosis which only happens in reproductive organs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what happens during meiosis

A

DIVISION 1:
1) Before the cell starts to divide, it duplicates its DNA (so there’s enough for each new cell). One arm of each X-shaped chromosome is an exact copy of the other arm.

2) In the first division in meiosis (there are two divisions) the chromosomes line up in pairs in the centre of the cell. One chromosome in each pair came from the organism’s mother and one came from its father.

3) The pairs are then pulled apart, so each new cell only has one copy of each chromosome. Some of the father’s chromosomes and some of the mother’s chromosomes go into each new cell.

4) Each new cell will have a mixture of the mother’s and father’s chromosomes. Mixing up the genes like this is really important it creates genetic variation in the offspring.

DIVISION 2:
5) In the second division the chromosomes line up again in the centre of the cell. It’s a lot like mitosis. The arms of the chromosomes are pulled apart.

6)You get four haploid daughter cells - these are the gametes. Each gamete only has a sinole set of
chromosomes. The gametes are all genetically different.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is asexual reproduction

A

divide by mitosis, results in two diploid daughter cells, which are genetically identical to each other and to the parent cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what is sexual reproduction

A

involves meiosis and the production of genetically different haploid gametes, which fuse together to form a diploid cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

asexual reproduction advantages

A
  • produce lots of offspring quickly as it’s independent
    e.g. bacteria E. coke can divide every half an hour
  • only one parent is needed, can happen whenever without waiting
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

asexual reproduction disadvantages

A
  • no genetic variation
  • if environment changes and conditions become unfavourable, the whole population may be affected
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

sexual reproduction advantages

A
  • creates genetic variation
  • if environment changes, more chance some will survive
  • can lead to natural selection and evolution
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

sexual reproduction disadvantages

A
  • takes more time and energy
  • two parents are needed, can be a problem if one is isolated
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

what is DNA made up of

A

polymers made up of lots of repeating units called nucleotides

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

what is a nucleotides

A

one sugar molecule, one phosphate molecule and one base

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what are the 4 bases called

A

adenine
thymine
cytosine
guanine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what bases pair together

A

A,T
G,C

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

how is DNA stored

A

chromosomes which contain genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

how do you extract DNA from fruit

A

1)Mash some strawberries and then put them in a beaker containing a solution of detergent and salt. Mix well. The detergent will break down the cell membranes to release the DNA. The salt will make the DNA stick together.

2) Filter the mixture to get the froth and big, insoluble bits of cell out.

3) Gently add some ice-cold alcohol to the filtered mixture.

4) The DNA will start to come out of solution as it’s not soluble in cold alcohol. It will appear as a stringy white precipitate (a solid) that can be carefully fished out with a glass rod.

22
Q

how are proteins made

A

by reading the code in DNA

23
Q

what is a mutation

A

a rare, random change to an organisms DNA base sequence which can be inherited

24
Q

what is a genetic variant

A

a different version of the gene

25
Q

what is an amino acid

A

protein chains

26
Q

what is transcription

A

the process by which a cell makes an RNA copy of a piece of DNA which then carries the genetic information needed to make proteins in a cell. It finally carries the information from the DNA in the nucleus of the cell to the cytoplasm, where proteins are made.

27
Q

what is translation

A

the process by which a cell makes proteins using the genetic information carried in messenger RNA which then is made by copying DNA, and the information it carries tells the cell how to link amino acids together to form proteins.

28
Q

what does non-coding do

A

binding of RNA polymerase

29
Q

what is the pea plant experiment

A
  1. In one experiment, Mendel crossed two pea plants of different heights - a tall pea plant and a dwarf pea plant. The offspring produced were all tall pea plants.
  2. He then bred two of these tall offspring together. He found that when the offspring from the first cross were crossed with each other, three tall offspring were produced for every one dwarf offspring overall. In other words, he produced a 3 : 1 ratio of tall : dwart plants.
30
Q

what were mendel’s 3 important conclusions

A
  1. characteristics in plants are determined by ‘hereditary units’
  2. hereditary units are passed on to offspring unchanged from both parents, one unit from each parent
  3. they can be dominant or recessive, if there is both the dominant will be displayed
31
Q

what is an allele

A

different versions of the same gene

32
Q

homozygous

A

the two alleles of the particular gene is the same

33
Q

heterozygous

A

the two alleles of the particular gene is different

34
Q

how is a dominant allele shown

A

D (capital)

35
Q

how is a recessive gene shown

A

r (mini)

36
Q

what is your genotype

A

combination of alleles you have

37
Q

what is your phenotype

A

alleles determine what characteristics you have, the combinations of alleles give rise to different phenotypes

38
Q

what is monohybrid inheritance

A

inheritance of a single characteristics, can be used to show how recessive and dominant traits for a single characteristic

39
Q

what can a genetic diagram show

A

how sex is determined in humans

40
Q

how many pairs of chromosomes are found in every human body cell

A

23 matching pairs

41
Q

what is the symbol of female chromosomes

A

XX

42
Q

what is the symbol of male chromosomes

A

XY

43
Q

example of genetic disorder

A

cystic fibrosis which is recessive

44
Q

why do alleles arise

A

due to genetic mutations

45
Q

what is a mutation

A

changes to the base sequence of DNA

46
Q

what do mutations have an effect on

A

phenotype

47
Q

what is the human genome project

A

thousands of scientists from all over the world worked together to find every single human gene. found the locations of around 20,500 genes.

48
Q

prediction and prevention of diseases

A

many diseases are caused by the interaction of different genes
e.g. if they knew what genes did what to people they could tailor a lifestyle for them

49
Q

testing and treatment for disorders

A

inherited disorders are caused by the presence of one or more faulty alleles in a persons genome, they can identify disorders much more quickly than the past.

50
Q

new and better medicine

A

they can design new drugs which are tailored to different people with a particular genetic variation

51
Q

what are the 3 drawbacks to the human genome project

A
  1. increased stress
  2. geneism
  3. discrimination