B1 and B2

DNA

A polymer in which the monomers are nucleotides. Each nucleotide includes one of the four bases (adenine, thymine, cytosine, or guanine)

genetic code

the order of bases in a genome. the genetic code is modelled using the letters A T C G to represent the bases. the order of the bases in a gene is the code for protein synthesis

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phenotype

the phenotype is the characteristic that results from this combination and interaction with the environment

job of genes

Each gene codes for a particular sequence of **amino acids** in order to make a specific protein

genetic variant

A different version of a gene

DNA

a polymer made up of nucleotides, forming two strands in a double helix

genome

All the genetic material of a cell is the organism’s genome. In most organisms the genome is packaged into chromosomes.

what are long molecules of DNA

Chromosome

sections of DNA

gene

where is the genetic material of a cell that doesn’t have a nucleus located?

in the cytoplasm

gamete

Gametes are the female and male sex cells - eggs and sperm

Homozygous alleles

identical alleles for a particular gene/characteristics

Heterozygous alleles

different alleles for a particular gene

dominant allele

An allele that is always expressed even if only one copy is present

recessive allele

An allele that is only expressed if an individual has two copies of it

sex determination

one pair of chromosomes determines the sex of the offspring

steps of genetic engineering

• isolating and replicating the required gene(s)

• putting the gene(s) into a vector (e.g. a plasmid)

• using the vector to insert the gene(s) into cells

• selecting modified cells

what is genetic engineering?

A process which involves modifying the genome of an organism to introduce desirable characteristics.

communicable disease

A disease caused by viruses, bacteria, protists or fungi that can be passed on from one organism to another.

non communicable disease

A disease that is not spread through infection or other people but are associated with genetic, environmental, and lifestyle factors.

a viral infection in humans

influenza (virus)

a fungal infection in humans

athletes foot (fungi)

a bacterial infection in humans

salmonella (bacteria)

a protist infection in humans

malaria (protist)

a sexually transmitted infections in humans

HIV/AIDS (virus)

how are platelets adapted to their function

They contain proteins on their surface that allow them to stick to breaks in the blood vessel wall and also to stick to each other.

a viral disease found in plants

tobacco mosaic virus

a fungal disease found in plants

ash dieback

a bacterial disease found in plants

crown gall disease

the physical defence that makes it difficult for pathogens to enter the blood

the skin

chemical defence that make it difficult for pathogens to enter the blood

mucus, tears, saliva, stomach acid

what do white blood cells do

destroy pathogens

how do white blood cells recognise antigens on pathogens

they have receptors

what are different white blood cells adapted to do (3)

* ingest and digest pathogens
* produce antibodies to disable them
* tag them for attack by other white blood cells

what are memory cells

Once the body has made antibodies against a pathogen, memory cells stay in the body to make antibodies quickly upon re-infection (immunity)

how can the spread of communicable diseases be prevented in humans (6)

* vaccination
* contraception
* hygiene
* sanitation
* sterilising wounds
* restricting travel

how are monoclonal antibodies are produced

* antigen injected into an animal
* antibody-producing cells taken from animal
* cells producing the correct antibody selected then cultured

what are monoclonal antibodies?

antibodies that can be produced in a lab using cultured clones of a white blood cell to produce antibodies against a particular antigen

how can monoclonal antibodies be used in diagnostic tests

they are providing diagnostic tests with greater sensitivity and specificity.

These tests give faster and more accurate results, which enables decisions about to be made more quickly and based on more accurate information

how are monoclonal antibodies can be used to treat cancer

* produce monoclonal antibodies specific to a cancer cell antigen
* inject the antibodies into the blood
* the antibodies bind to cancer cells, tagging them for attack by white blood cells
* the antibodies can also be attached to a radioactive or toxic substance to deliver it to cancer cells

where do **Prokaryotes** cells store genetic information

Their genetic material is in the cytoplasm and includes small loops of DNA called **plasmids**

**Chromosomes**

long, thin, threadlike structures made from molecules of DNA that store genetic information.