Biology test Flashcards
What’s DNA
It’s the chemical that all the genetic information in a cell is made up from
What does mRNA do
It’s a replicate of the code from DNA and acts as a messenger between DNA and ribosome so protein can be made
What’s a mutation
It’s a random change in an organism’s DNA
What do mutations do and cause
They change the sequence of the DNA bases in a gene hitch produce genetic variant
What is sexual reproduction and what’s the process called
It’s the fusion of a male and female gametes which the offspring will contain a mixture of their parent’s genes. It’s caused by meiosis
What Is asexual reproduction and what’s the process called
A single parent passes their genes to the offspring without the need of fusion between gametes. It’s caused by mitosis.
What are advantages of sexual reproduction(4 total)
1)The offspring receives a mixture of two sets of chromosomes which causes variation
2)Variation increases the chance of the species surging in a changing environment
3)Individulas with characteristics make them better adapted so better chance of survival, breeding and passing genes.
4)Using selective breeding we can produce animals with desired characteristics.
What are the advantages of asexual repoduction(4 total)
1)Only need 1 parent
2)It uses less energy as they don’t need to find mates
3)It’s faster than sexual reproduction
4) Many identical offspring can be produced in favourable conditions
What sex chromosome do men and women have
Men have XY and women have XX
What alleles do you have when it’s homozygous.
(Tip it has 3 repeated o ). when an organism has two alleles for a particular gene that are the same(CC or cc)
What alleles do you have when it’s heterozygous
If it’s two alleles for a particular gene are different(Cc)
What’s a dominant gene
If two allies are different it’s the allele which can only determine what characteristics is presented(C)
What’s a recessive gene
Genes only expressed when homologous(the same pair e,g cc)
What’s a genotype
It’s the genes which are inherited
What’s a phenotype
It’s the genes which are expressed and seen
What is co dominance
Both genes for the character/trait are expressed(reXwhite=pink)
What’s the role of DNA in making protein
Ribosomes use the code in DNA which is found in the nucleus. However DNA is too large to get out. mRNA carries the code between the two which is made by copying the code from DNA.
What’s the effect of mutations.
Mutations change the sequence of a DNA based in a gene which produces a genetic variant. Mutations to a gene sometimes lead to changes in the protein it codes for
Furthermore what’s the effect of mutations on genetic inheritance
It may introduce a change in DNA sequence which can be passed to the offspring. It may lead to a new trait or genetic disorders.
What is the process of meiosis
It occurs in humans. Firstly the cell duplicates its genetic information and the chromosomes arrange into pairs. First division is when the chromosomes are split so each new cell only has a copy of each chromosome. In the second division, the chromosomes line up again in the centre and are pulled apart. You get 4 gametes. Each genetically different.
What is the process of mitosis.
The cell grows and increase in sub cellular structures. Then DNA is duplicated. The chromosomes line up and are pulled apart. The nucleus divides and cytoplasm and cell membrane Which produces 2 identical daughter cells.
Differences between meiosis and mitosis(6).
MITOSIS:1 STAGE meiosis 2
2 DAUGHTER CELL and 4 gametes
IDENTICAL. variation
DIPLOID(2N) haploid(n)
QUICK slow
GROWTH REPAIR sex reproduction
What’s cystic fibrosis and what allele type.
Genetic disorder of membrane. Produces a lot of thick sticky mucus in air passage and pancreas. Recessive allele so homozygous recessive alleles to be affected.(cc)
What’s polydactyly and what allele causes it
It where a baby is born with extra fingers or toes. It’s caused by a dominant allele so if you get a single dominant allele you get the disease
How can embryos be screened for genetic disorders
During IVF,before implanting the fertilised egg into the womb, they remove a cell from each embryo to analyse the genes.
Advantages of genetic screening(4)
It will stop people suffering
Provides a choice with abortion
Allows parents to emotionally and finically prepare
Reduces health care cost over time
Disadvantages of genetic screening(5)
Increases prejudice as it kills people with genetic disorder
It’s expensive to screen
May put embryo at risk of miscarriage
Screening may harm mother
Reduces people with disorder
What happens during Genetic Engineering
It’s the deliberate modification of an organisms geness
