genetics Flashcards
1
Q
what does sexual reprodcution require
A
fertillisation and 2 parents
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what is fertillisation
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the fusion of male and femake gametes
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how mnay chromomes do gametes have
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23
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what process does sexual reproduction happen by
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meiosis
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do plants undergo sexual reproduction or asexula reproduction
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both
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why is there gentic variation in seuxal reproduction
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the offspring has half the femeale chromomes and half the male chomomesom
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Q
do animals undergo sexual or asexual reproduction
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sexual
8
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what does asexual reproduction require
A
one parent
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A
9
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why is there no genetic variation in asexual reproduction
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the offspriig is going to be geneetically identical and no mixing of genetic infor
10
Q
do eukaryotes undergo asexual or sexual reproduction
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asexula
11
Q
do eukaryotes undergo mitosis or binary fusion
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mitsosis - two idnetical cells formed from one
12
Q
what process are gametes formed by
A
meiosis
13
Q
do bacteria undergo binary fusion or mitosis
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binary fusion
14
Q
do bacteria reproduce asexaully or sexually
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asexually
15
Q
what are the pros of asexual reproduction
A
1.only requires one parent
2. quick and easy
16
Q
what are the cons of asexaul reproduction
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- more suceptile to disease - if one offspring gets it the rest will have it because they are gentically idnetical
- no genetic variation
- can’t adapt to conditions
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Q
what are cons of sexual reproduction
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- sexual reproduction requires 2
- time consuming
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what are pros of sexaul reproduction
A
- less suceptiple to disease because there is genetic variation
- can adapted to condions like climate change
19
Q
haploid
A
half the chromomes
20
Q
diploid
A
full amount of chromomes
21
Q
how much is an haploid cell
A
23
22
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how much is in a diploid cell
A
46
23
Q
how many gametes are there after meiosis
A
4, that are not gentically idenitcal
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why are the gametes produced after meiosis not gentically identiccal
chromomesomse shifted, resulting in random chromosomes in each cell
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what happens after meiosis
1. gametes fertilise to produce a cell with 4 chromsomes
2. the cell will undergo mitsosi
3. embryo will form
4. diffrentiation will take place
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what is a gamete
a cell with half the number of chromosomes of the parent
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what are clones
offspring that are gentically identical
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what is reduction division
when the number of chromosomes in gametes halves
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what is DNA
a polymer made from 2 strands ehich cooil around each other
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what are nucleotides
repeating unit in DNA and RNA that consist of sugar, a phosphate group and a base
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what are complementary base pairings
when one of the four bases in DNA pair with another four bases
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what is a genome
found in the cells nucleus and contains the full dna of an organism
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what is a gene
small part on a chromosome
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what is a codon
a sequence of three bases that is that code for a particular amino acid
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what is a population
the number of one specieis in a habitat
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what is an allele
diffrent forms that each gene has
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does dna have a double or single helix
double helix
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what are the two main stages of protein synthesis called
transcription and translation
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where is the nucleoid found
dna
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what is variation
it means that the individual in a popilation show difference in characteristics
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what is discontinous variation
when there is a limited number of values that a limited number of values that an individual can possess
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why is dna a polymer
it is made of many nucleotides joined in a chain
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in organisms all the cells that have a nucleus will have a complete set of chromomes, gametes as an exception to this. what does this mean
thar cells contain every gene required to create every protein the organism will ever need
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how many main stages are there in protein synthesis
2
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what is the genegttic matriel in the nucleus of cells made from
dna `
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what happens during tranlsattion
1. the strand of mRNA travels out of the nucleus
2. in the cytoplasm, a ribosome attactches to the mRNA strand
3. A tRNA molecule pair with each codon
the ribsomes joins together the amino acids carried by the tRNA molecules
4. this results in the formation of a polyppeptice
5. the types and order of amino acids in the chain cause it to fold into a specific shape
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what happens during transcription
1. inside the nucleus RNA polymerase attactches to a non coding section of dna
2. the enzyme, rna polymerase seperate the two strands of DNA
3. rna polymerase continues to move along the dna to reach the coding region of a gene
4. rna polymerase adds complementary rna nucleotides to the template strand
5. rna polymerase links the rna nucletiddes together to form a strand of mRNA
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what does dna stand for
deoxyribonucleic acid
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what is dna made up of
nucleotiddes
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what contains the instruction for proteins
a gene
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what is dna organised in
arranged chromsomes
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is a gene larger than a chromsome
no a chromosome is larger than a gene
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how many bases does ammino acids code for
3
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how many types of nuclleotides are there
4
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what is each nucleoid made up of
a phophate group, a base and a simple pentose sugar
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what has alternating sugar and phophate section
long strands of DNA
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what sends instruction for a particular sequcne of amino aicds, to make specific proteins
each gene
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what is A paired with
T
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what holds the base pairs and two strands together
weak hydrogen bonds
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what are the four bases in dna
1. adenine (A)
2.Thymime (T)
3. guanine (G)
4. cytosine (C)
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what can turn the genes on or off in a cell
non coding dna parts
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what is C paired with
G
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what do ribosome do
carry out protein synthesis in the cytoplasm of the cell
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does all dna codes proteins
no
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what could poteintially effecgt how genes are expressed
mutations
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how many levels of organisattion in a genome
3
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what are the three names of the levels of organisation in a genome
dna, chromomsomes and genes
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what happens if a mutation codes for a sligtly altered enzyme protein with a diffrent shape
an enyme may no longer fit the substrate bidning site
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whar brings ammino acids to the ribosome
carrier molecules
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what three thing are made from proteins genes, send instructuons to create the protein needed from amino aicds
enzymes, horomes and antibodies
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what is the role of RNA polymerase
too bind to non coding dna in front of the gene and produce a complementary mRNA strand from tge codubg DNA of the gene
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what does the order of bases control
the order the amino acids are formed to produce a singular protein
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what does a protein chain form when completed
a uniqye shape which allows the protein to carry out its role effectively, its role could be as an enzyme or a hormone
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what happens when mutations occur over time
there can be genetic variants
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what happens before transcription occurs
RNA polymerase binds to the non coding part of the DNA in front of the gene
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what was mendel's hypothesis
1. the inits of inheritance are passed on to offspring unchanged
2.characteistics are held as sepeare units of inheritance
3. each unit of inheritance exists in two forms, dominant and recessive
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what will happen if a mutation occurs in the non coding part of the DNA
the mutation could effect how well the RNA polymerase can bind to the non coding part of the \dna
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what did mendel propsed the unit of inheritance as
genes
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why did scientist not undestrand mende;'s work
scientist didn;t have microscopes and therefore didn't know about the existence of chromosomes
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what did mendel study
inheritance of certain charactersitics in peas, while working in the monstery gardens observed if he crossbread white and red flowers. the red flowers were more dominant than the white
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name two characteruitcs controlled by a single gene
hair colur and eye colour
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each allele codes for a diffrent....
protein
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what is red green colour blindness due to
the mix of allels they possess
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what is inheritance
when living things reproduce and pass on characteristics to their offspring in genes
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what does homozygous mean
when two allels are the same
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what represents a homozygous allel
either two capital letters or two lower case
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what represents a hydroxygous allele
a capital and a lower case
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what does hetrozygous mean
when two allels are diffrent
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what is a genotype
the set of genes that an organism has
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what is a phenotype
the physical characterisitc of an organism
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what does dominant mean
an allele that controls the characteristic whenver presented, capital letter
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what does reccessive mean
an allels who characterisitcs only show up when its present on both chromosomes
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what chromosomes do girls have
xx
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what chromsomes do boys have
xy
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why can you get the same sex
because fertillisation is random
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what does it mean if a conditionis caused by a dominant allele, one of the parents has the condition but there are some offspring without the condition
the parents condition must be hetrozygous
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what is a genetic cross
a way of modelling potenital outcome from mating two parents where the phenotype and genotype are usually know
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why do we use characteristics that are controlled by a single gene
it is easy to see the effect in the next generation and beyond
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who is ffamous for creating the punett square diagram
british genetiscist reginald punnet
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what is a punnett square
a tool used to predict the probality of genotypes in future off spring
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what ddoes a family tree help do
to show how genetic disorders are inherited in a family
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what are family tees used to do
workout the probablity thatva member of the family will inherit a disorder
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what is colour blindness
a sex linked genetic disorder that a person is born with
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what causes colour blindness
a faulty alele carried on the x chromsome
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which one is bigger the x or y chromsome
x
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why are more men than women are affected by the disorder
women need two copies of the faulty recessive allele to be colour blind, whilst men only need one copy
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is blood group inherited
yes
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how many possible blood groups are there
4
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what are the names of these 4 possible blood groups
1. A
2. B
3. AB
4. O
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how many diffrent allels does the gene for blood have
three
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what are the three diffrent allels that the gene for blood has
: IA , IB and IO
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what two allels fr blood groups are co dominant
IA and IB
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what does it mean if a person is codominatn
if a person has the genotype IA and IB then they are blood group AB. Both allels are equally as dominant
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which of the four possible blood groups is recessive
IO
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how many of the chromosomes control characteristics
22
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what are sex chromomes
the 23rd pair of chromsomes that carry the genes that determine sex
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because sex chromomes are not identical to each other, what are they called
x and Y
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at what stage is sex determined at
fertillisation
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why is there a 1in 2 chance of the offspring being male/female
becayse it depnds on whether a sperm containing an x chromosome or Y chromosome fertillises the egg and there are equal numbers of these
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what do the genome and its interaction with the environment influence
the development of a phenotuype in an organism
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varation within a population of a species is usually..
extensive, mostly arising from mutations
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what is produced from the same egg and sperm
identical twins, they show very little/no genetic variation
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what is a result of multiple genes interacting rather than single gene inheritance
most phenotypic features
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can continous or discontinous data take any value between two limits
continous
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what is continous varation
when the diffrence in chracteriscs is continous
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what are examples of continous data
lenth mass time
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does continous or disconitnous data values only have on set of number option
discontinous
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what is discontinous varaition
when difference in characterics are discontinous
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what are exxamples of discooontinous data
shoe size a blood group
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would you use a bar graph/historgam for discontinous or continuous data
discontinous
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would you draw a line graoh for cintinous or discontinous data
continus
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what is envriomental variation caused by
how the enviroment effewcts the individual
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what is genetic variation causedby
the diffrence in allels
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what are 3 factors influenced by both gentic and environmental variation
1. skin colour
2. weight
3. altheticism
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name 5 human phenotypes which are cuased by genetic variation
1. eye colour
2. natural hair coloue
3. nose shape
4. ear lobe shape
5. blood group
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name 5 human phenotypes i9nfluncd by enviromental variation
1. hair length
2. accents
3. tatoos
4. scars
5. language spoken
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what are three causes of variation
1. diffrences in enviromental conditions have led to vairation
2. diffrences in the genes indivudlas have inherited due to mutation and sexual reproduction
3, a combination of both genetic and environmental causes
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what is the human genome prohect
an international scientific research prohect set up to map all the genetic info in a human being
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3 reasons why the human genome is important
1. to enable scientists to search for the genes linked to different types of disease to look for possible treatment or correction
2. to enable doctors to better understand and treat inhetiedd disorders
3, to be able to trace historic human migration patterns
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where can mutations occur
in a gamete or body cell
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where do genetic variation arise rom
mutations
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what occurs continously during cell division
mutations
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do genetic mutation alter the phenotype
no, bur some will have a small effect on the phenotype
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what can happen if a phenotype is suited to an environmental change
can lead to a relatively rapid change in the species
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what is mutation
a change in the dna sequence of a gene
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how many types of mutatations are there
4
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what are the names of the 3 types of mutation
insertion deletion subsition and neutral
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what are are carcinogerns
cancer causing mutations
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what is a spontanous mutation
a mistake made when dna is copied during the production of gametes
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what does does it mean if there is a spontaneous mutation
that the mutation wil be inherited by the offspring after fertilization
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what increases the chances of mutation
radiationsa
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what are mutagens
anything thaat causes a mutation
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if you smoke what aare you more likely to get
carcingens
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what do useful mutations help a species to do
adapt to an enviroment and give a species an advantage
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what would happen if there is a mutation in the non coding part of the DNA
may result in RNA polymerase not binding well reducing trasnciption. other non coding mutations can result in RNA polymerase binding better and producing mRNA
