reproduction and inheritance Flashcards
(91 cards)
1
Q
what type of cells are human cells
A
diploid
2
Q
what does diploid mean
A
2 comes of each chromosome arranged in pairs
3
Q
how many chromosomes does a human cell have
A
46
4
Q
where are chromosomes found
A
nucleus of the cell
5
Q
what are chromosomes
A
long lengths of DNA coiled up
6
Q
what is a gene
A
a short section of DNA
7
Q
what is each separate gene
A
a chemical instruction that codes for a particular protein
8
Q
what are different versions of the same gene called
A
alleles
9
Q
what I the structure of DNA
A
double helix
10
Q
four different bases
A
adenine
cytosine
guanine
thymine
11
Q
what compliments A
A
T
12
Q
what compliments C
A
G
13
Q
what are the two strands of DNA held together by
A
bases
14
Q
what are proteins made up of
A
chains of amino acids
15
Q
how does each protein have a different function
A
the chains fold up to give each protein a different, specific shape, therefore the enzymes have different active sites
16
Q
what is a codon
A
each amino acid is coded by a sequence of 3 bases in the gene
17
Q
how Manu possible codons are there
A
64
18
Q
how many amino acids are there
A
20
19
Q
what stages are proteins made in
A
transcription
translation
20
Q
where are proteins made
A
ribosomes
21
Q
why can’t DNA move to the ribosome
A
it is found in the nucleus and is too big to move out
22
Q
what is used to get info from the DNA to the ribosomes
A
messenger RNA (mRNA)
23
Q
what is different about the bases in mRNA than in DNA
A
uses uracil (U) instead of thymine (T)
24
Q
what enzyme joins together the base sequence to make mRNA
A
RNA polymerase
25
4 stages of transcription
- RNA polymerase binds to a region of non-coding DNA in front of a gene
- the 2 DNA strands unzip and the RNA polymerase moves along one of the strands in the DNA
- It uses the coding DNA in the gene as a template to make the mRNA. Base pairing between the DNA and RNA ensures that mRNA is complimentary to the gene
- Once made, the mRNA molecule moves out of the nucleus and joins with a ribosome in the cytoplasm
26
what is it called when the protein is assembled in protein synthesis
translation
27
4 stages of translation
- amino acids are brought to the ribosome by another RNA molecule called tRNA
- the order in which the amino acids are brought to the ribosome matches the order of the codons in mRNA
- part of the tRNA's structure is called an anticodon as it is complimentary to the codon for the amino acid. the pairing of the codon and anticodon makes sure that the amino acids are brought to the ribosome in the correct order
- the amino acids are joined together by the ribosome making a protein
28
what type of reproduction involves mitosis
asexual reproduction
29
what is asexual reproduction
asexual reproduction involves only one parent. the offspring have identical genes to the parent so there is no variation between parent and offspring
30
what is mitosis
when a cell reproduces itself by splitting to form 2 cells with identical sets of chromosomes
31
what organisms reproduce asexually
bacteria and plants
32
process of mitosis
- the DNA duplicates, forming X-shaped chromosomes, each arm a duplicate of the other
- the chromosomes line up at the centre of the cell and cell fibres pull them apart, each arm of the chromosomes go to opposite ends
- membranes form around each of the sets of chromosomes becoming nuclei of each cell
- cytoplasm divides leaving 2 identical cells
33
what type of reproduction involves meiosis
sexual reproduction
34
what is sexual reproduction
the fusion of male and female gametes. Because there are 2 parents, the offspring contain a mixture of their parent's genes
35
what is meiosis
meiosis produces 4 hapolosid cells whose chromosomes are not identical
36
process of division 1 meiosis
- DNA duplicates and forms x-shaped chromosomes, each arm is an exact copy of the other
- chromosomes line up I pairs in the centre of the cell, one chromosome in each pair is from the mother and one from the father
- pairs are pulled apart, so each cell has only one copy of each chromosome
- each new cell has a mixture of the mother's and father's
37
process of division 2 meiosis
- chromosomes line up in the centre of the cell, the arms of the chromosomes are pulled apart
- this results in 4 haploid gametes, genetically different
38
male reproductive part of a plant
stamen
39
female reproductive part of a plant
carpel
40
what does the stamen consist of
anther and filament
41
what does the carpel consist of
ovary, style and stigma
42
what is the anther
contains pollen grains, which produce male gametes
43
what is the filament
the stalk which supports the anther
44
what is the stigma
the end part which pollen grains attach to
45
what is the style
rod-like section that supports the stigma
46
what is the ovary
contains the female gametes inside ovules
47
what is pollination
the transfer of pollen from an anther to a stigma so that the male gametes can fertile the female gametes
48
what is cross pollination
where pollen is transferred from the anther of one plant to the stigma of another
49
what do plants that cross-pollinate rely on
insects or the wind
50
how are some plants adapted for insect pollination
- brightly coloured petals
- scented flowers
- big sticky pollen grains
- sticky stigma
51
how are some plants adapted for wind pollination
- small dull petals
- no strong scents
- lots of small light pollen grains
- long filaments that hang outside the flower
- large feathery stigma
52
what happens during plant fertilisation
- pollen grains lands on stigma
- pollen tube grows out of the pollen grain and down through the style to the ovary and into the ovule
- nucleus from the male gamete moves down the tube to join with the female gamete in the ovule
- nuclei fuse together to make a zygote, dividing by mitosis to form an embryo
53
what is fertilisation
the fusion of gametes
54
what is germination
when the seed starts to grow
55
what conditions do a seed need to grow
water
oxygen
suitable temp for enzymes
56
what are runners
fast-growing stems that grow out sideways just above the ground, they take root at various distances away for new plants to grow
57
when is stage 1 of the menstrual cycle
days 1-4
58
when is stage 2 of the menstrual cycle
days 4-14
59
when is stage 3 of the menstrual cycle
day 14
60
when is stage 4 of the menstrual cycle
days 14-28
61
what happens in stage 1 of the menstrual cycle
uterus lining breaks down
62
what happens in stage 2 of the menstrual cycle
uterus lining builds up again into a thick spongy layer ready for a fertilised egg
63
what happens in stage 3 of the menstrual cycle
an egg develops and is released from the ovary, ovulation
64
what happens in stage 4 of the menstrual cycle
wall is maintained for about 14 days, if no fertilised egg implants the cycle starts again
65
4 hormones in menstrual cycle
FSH
oestrogen
LH
progesterone
66
where is FSH produced
pituitary gland
67
what does FSH do
causes an egg to mature in one of the ovaries
stimulates the ovaries to produce oestrogen
68
where is oestrogen produced
ovaries
69
what does oestrogen do
causes the lining of the uterus to grow
stimulates release of LH
70
where is LH produced
pituitary gland
71
what does LH do
stimulates release of an egg at day 14
72
where is progesterone produced
ovaries
73
what does progesterone do
maintains the lining of the uterus in the second half of the cycle
74
what is the purpose of the placenta
lets blood of the embryo and mother get very close to allow the exchange of food, oxygen and waste
75
what is the amnion membrane
surrounds the embryo and is full of amniotic fluid
76
what is amniotic fluid
protects the embryo against knocks and bumps
77
what are most characteristics controlled by
several genes interacting
78
how many copies of each gene do you have
2
79
what is an allele
different versions of the same gene
80
what is a genotype
the allele that you have
81
what is a phenotype
the characteristics the alleles produce
82
what does homozygous mean
two of the same allele
83
what does heterozygous mean
two different alleles
84
what does co-dominant mean
neither allele is recessive so you show characteristics from both alleles
85
how do you show genetic diagrams
Punnett square
86
what is variation in animals due to
genes and environment
87
what are plants characteristics due to
- sunlight
- moisture level
- temp
- mineral content
88
what is the theory of evolution
life began as simple organisms from which more complex organisms evolved
89
what does a mutation do
changes the sequence of the DNA bases in a gene, producing a genetic variant
90
how do mutations affect protein
mutations change the code for amino acids that make proteins leading to changes in the protein it codes for
91
what increases the chances of mutation
ionising radiation and mutagens
