Biology paper 2
Gametes
Sex cells, sperm and egg. Chromosomes are single not paired. They are made by meiosis
Fertilisation
The fusion of the male and female gametes(sperm and egg). The genetic information gets mixed
providing variation in the offspring
Asexual reproduction
Only one parent and produces genetically identical offspring (clones). No gametes involved so more
energy and time efficient in favourable conditions. Increases the risk of exctitin
Sexual reproduction
1. Chromosomes are copied
2. Cells divide to form 4 daughter cells
3. Chromosomes are single
4. Cells are fertilised
5. The cell has chromosome pairs
6. Mitosis occurs to form an embryo
It provides variation and therfore provides a survival advantage
Malaria reproduction
In the human host malaria reproduces asexually. In a mosquito vector it reproduces sexually.
Fungi reproduction
Releases spores in air or water is asexually or can be sexually.
Plant reproduction
Sexually to produce seeds or asexually using runners or bulb division.
DNA
Determines our inherited structure and is found in chromosomes.
Gene
A small section of DNA on a chromosome. Encodes for a different amino acid and protein. The order of
amino acids determines the shape and function.
Human genome
It is the entire genetic material that makes a human. Understanding it will allow us to search for certain
genes linked to disease, understand inheritance and trace migration patterns.
Protein synthisis
, Biology paper 2
How proteins are made. It has two parts transcription and translation.
Transcription
Happens in the nucleus. The base sequence is copied to a mRNA which leaves the nucleus
Translation
Happens in the cytoplasm. The mRNA attaches to a ribosome. tRNA brings amino acids which the
ribosome puts together depending on the mRNA sequence. Chain folds up to form shape
Mutation
A change to the base sequence. Most of the time there is no effect, sometimes different amino acids are
created so the genes doesn't do its fuction is is on when it shouldn't be
Alleles
Different versions of the same gene
Genotype
Tells us the alleles present in a person.
Ee = heterozygous ee = homozygous.
Phenotype
Tells us the characteristics caused by the alleles. A dominant allele will show in the phenotype even if
there is only one copy
Cystic Fibrosis
Disorder of the cell membranes. Recessive conditions meaning you need a homozygous small pair to get
it e.g. cc
Polydactyly
Have extra fingers or toes. Dominant condititon meaning you only need one big allele to get such as in a
heterozygous pair e.g. Pp
Embryo Screening
Embryos are tested for certain conditions and only normal embryos are imprinted. It is very expensive,
many embryos are destroyed and may lead to screening for desired characteristics such as intelligence or
beauty.
Gender
xy = male xx = female
Variation
Gametes
Sex cells, sperm and egg. Chromosomes are single not paired. They are made by meiosis
Fertilisation
The fusion of the male and female gametes(sperm and egg). The genetic information gets mixed
providing variation in the offspring
Asexual reproduction
Only one parent and produces genetically identical offspring (clones). No gametes involved so more
energy and time efficient in favourable conditions. Increases the risk of exctitin
Sexual reproduction
1. Chromosomes are copied
2. Cells divide to form 4 daughter cells
3. Chromosomes are single
4. Cells are fertilised
5. The cell has chromosome pairs
6. Mitosis occurs to form an embryo
It provides variation and therfore provides a survival advantage
Malaria reproduction
In the human host malaria reproduces asexually. In a mosquito vector it reproduces sexually.
Fungi reproduction
Releases spores in air or water is asexually or can be sexually.
Plant reproduction
Sexually to produce seeds or asexually using runners or bulb division.
DNA
Determines our inherited structure and is found in chromosomes.
Gene
A small section of DNA on a chromosome. Encodes for a different amino acid and protein. The order of
amino acids determines the shape and function.
Human genome
It is the entire genetic material that makes a human. Understanding it will allow us to search for certain
genes linked to disease, understand inheritance and trace migration patterns.
Protein synthisis
, Biology paper 2
How proteins are made. It has two parts transcription and translation.
Transcription
Happens in the nucleus. The base sequence is copied to a mRNA which leaves the nucleus
Translation
Happens in the cytoplasm. The mRNA attaches to a ribosome. tRNA brings amino acids which the
ribosome puts together depending on the mRNA sequence. Chain folds up to form shape
Mutation
A change to the base sequence. Most of the time there is no effect, sometimes different amino acids are
created so the genes doesn't do its fuction is is on when it shouldn't be
Alleles
Different versions of the same gene
Genotype
Tells us the alleles present in a person.
Ee = heterozygous ee = homozygous.
Phenotype
Tells us the characteristics caused by the alleles. A dominant allele will show in the phenotype even if
there is only one copy
Cystic Fibrosis
Disorder of the cell membranes. Recessive conditions meaning you need a homozygous small pair to get
it e.g. cc
Polydactyly
Have extra fingers or toes. Dominant condititon meaning you only need one big allele to get such as in a
heterozygous pair e.g. Pp
Embryo Screening
Embryos are tested for certain conditions and only normal embryos are imprinted. It is very expensive,
many embryos are destroyed and may lead to screening for desired characteristics such as intelligence or
beauty.
Gender
xy = male xx = female
Variation
