B13 Flashcards
(72 cards)
1
Q
what are the 2 types of reproduction
A
sexual and asexual
2
Q
characteristics of sexual reproduction
A
- 2 parents are needed
- offspring will have genetic variation
- fusion of gametes
3
Q
characteristics of asexual reproduction
A
- 1 parent is needed
- offspring will be genetically identical to one another (clones)
4
Q
advantages of asexual reproduction
A
- enables an organism to populate a new habitat quickly
- make sures successful characteristics are passed on
- faster than sexual reproduction
5
Q
disadvantages of asexual reproduction
A
- no genetic variation so all organisms have the same weakness
- no genetic variation means it is difficult to adapt to the environment
6
Q
advantages of sexual reproduction
A
- genetic variation in offspring
- natural selection can be manipulated by humans to have a better yield
7
Q
what is meiosis
A
cell division of gametes only
8
Q
where does meiosis take place
A
in the reproductive organs
9
Q
how does meiosis work
A
- a gamete makes clones of chromosomes so it’ll have 92 chromosomes (46 pairs)
- similar pairs of chromosomes match up
- genes get swapped in the chromosome
- cell divides twice and then twice again
10
Q
is a gamete a haploid or diploid
A
haploid
11
Q
are gametes similar to each other
A
no they are not. each gamete is genetically different from one another
12
Q
what is the point of meiosis
A
- for making egg and sperm cells
13
Q
what are the male and female gametes of flowers
A
male - pollen
female - ovule
14
Q
how do flowers undergo sexual reproduction
A
the pollen of a flower pollinates another ovule creating a seed
15
Q
how do fungi reproduce
A
mostly asexually but at times sexually to
16
Q
how do fungi create gametes and what is the name of said gamete
A
spores are made by mitosis
17
Q
how does a fungi reproduce asexually
A
- spores are made by mitosis and are stores in fruiting bodies
- spores then become mycelium
- mycelium grown into the fungi
18
Q
how do fungi reproduce sexually
A
- 2 cells with different chromosomes mix to form a diploid cell
- meiosis occurs to form diploid spores
- the spores then form mycelium which grow into the fungi
19
Q
how do malaria in a mosquito reproduce
A
sexually in a human but asexually in a mosquito
20
Q
how do some plants grow by runner
A
a new, clone plant forms at the end of a runner by mitosis in asexual reproduction
21
Q
the steps of reproduction of malaria
A
- the parasite goes into the liver of a human where it goes into red blood cells
- the parasite bursts out of the rbc
- the infected blood is picked up by other mosquitos
- parasite reproduces asexually in mosquito guts
- parasite goes into mosquito saliva
- mosquito bites another human and infects them
22
Q
what is a chromosome
A
strands of dna in a double helix shape
23
Q
what is a gene
A
a section of a chromosome which controls a characteristic
24
Q
what is the sex chromosome of a female
A
2 x
25
what is the sex chromosome of a male
x and y
26
what does a gene code for
a specific sequence of amino acids which form a protein
27
what is a genome
all of the genetic material in an organism
28
has the human genome been sequenced
yes, it was done by unravelling the double helix
29
what were the outcomes of hgp
- detailed information about the genome
- identification of new genes - genes analysed for mutations causing a mutation
- identification of new drug targets
- preventative medicine
- identification of mutations
30
what is an allele
an alternate form of a gene that form due to a mutation
31
what is a nucleotide
the molecules which DNA and RNA are made from
32
what is dna
Dna is a form of polymer called polynucleotide
33
what does a nucleotide consist of
a sugar, a nitrogen base and a phosphate
34
how many bases are there in dna
there are 4 bases: A,C,G,T
35
what is the monomer of DNA
nucleotides
36
what forms the backbone of DNA
phosphate and the sugar
37
how many bonds do G and C have
3 bonds
38
how many bonds do A and T have
2 bonds
39
what is the central dogma of molecular biology
the theory that states genetic material only flows in one way
40
how does the central dogma of molecular biology work
DNA turns into mRNA which turns into proteins
41
whats the process called when DNA turns into mRNA
transcription
42
what's the process called when mRNA turns into proteins
translation
43
where does transcription take place
in the nucleus
44
where does translation take place
in the cytoplasm
45
what happens at transcription
DNA unwinds from the double helix shape. a hormone makes a copy of the DNA called mRNA. this mRNA leaves the nucleus and goes to the ribosomes
46
what happens at translation
each 3 bases of mRNA translate for a singular amino acid. the bases are ordered as the mRNA template of the DNA. this happens in the ribosomes in the cytoplasm. the amino acids are in the cytoplasm and are brought down to the ribosomes by carrier molecules to create a chain of amino acids which form a specific protein.
47
what happens after translation
the amino acid chain folds up to form a unique shape. this unique shape allows the protein to carry out its role effectively.
48
what is a mutation
a change when the genotype is copied differently from the original.
49
are mutations always bad?
no
50
what problems can mutations make
- enzymes' active site is changed so a different substrate fits
- active site changed so no substrates fit
51
what is gene expression
when a gene codes for a protein which is synthesised in a cell
52
what is an allele
the same gene in a different form
53
what is the genotype
a combination of alleles
54
what is the phenotype
the effect of the alleles on characteristics of an organism
55
what is homozygous
It is when two alleles in an organism are the same
56
what is heterozygous
It is when 2 alleles are not the same. The genotype is heterozygous
57
what is a dominant allele
an allele which is always expressed
58
what is a recessive allele
an allele which can only be expressed if there are 2 present
59
how are some diseases inherited
the inheritance of some faulty genes
60
what is polydactyl caused by
a dominant gene
61
what is polydactyl
a disease when a person has extra toes or fingers
62
what is cystic fibrosis
a disorder of cell membranes
63
wwhat is cystic fibrosis
a disorder of cell membranes
64
what is cystic fibrosis caused by
it is caused by a recessive allele
65
what is gene therapy
when a patient is given a healthy version of defectiv gene
66
is there a cure to inherited diseases
NO
67
what is embryo testing
when embryos are tested during pregnancy for alleles which cause inherited diseases.
68
what are the 2 types of embryo screening testing
1. amniocentesis
2. CVS
69
how does amniocentesis work and the pros and cons
involves removing the amniocentesis fluid (the fluid surrounding an unborn baby in the womb) and testing it. Cna only happen to someone women who have a high chance of genetic disorders. can also only happpen between 15-20 weeks of pregnancy. after having the test done there is a 0.5-1% chance of miscarriage.
70
how does chorionic villus sampling work? also state the pros and cons while you're at it
involves removing a bit of cells form the placenta using a needle and forceps.
The procedure can be descirbed as painful although there may be painful experiences which can be described being similar to cramps 1 or 2 days afterwards. Can happen 10-12 weeks during pregnancy.
risk of miscarriage is 2%.
71
what are the advantages of genetic screening
- fewer people with cycstic fibrosis are born which reduces health cost over time
- allows parents to finanically and emotionally prepare to live with a child with cycstic fibrosis
- reduces the number of people living with geneti disorders
72
what are the disadvantages of genetic screening
- puts the embryo at risk - higher chance of miscarriage
- it encourages abortion - religious people argue that the child has a right to life
- may cause harm to the mother
