genetics

DNA

chemical that genetic material is made up from, polymer in double helix shape

what is a chromosome?

long structures of DNA, found in pairs

what is a gene?

small section of DNA on a chromosome, that codes for a particular sequence of amino acids to make a specific protein

what is a genome?

entire set of genetic material in an organism

what are the benefits of understanding the human genome?

• identify genes linked to certain diseases

• knowing genes linked to inherited diseases improves understanding and development of treatment

• genomes can be used to trace migration of populations

what are nucleotides?

repeating strands of DNA (polymers)

what is 3 things are present in each nucleotide?

a sugar, a phosphate and a base

what is complementary base pairing?

• A - T

• C-G

where are proteins made?

ribosomes (in cytoplasm)

what is the process of protein synthesis?

• ribosomes use the code in DNA (in nucleus)

• mRNA copies the code from DNA, and acts as a messenger between the DNA and the ribosome (carries the code)

• the amino acids see brought to the ribosomes in the correct order by the carrier molecules

what are the functions of proteins?

• enzymes

• hormones

• structural proteins

what is the function of enzymes?

biological catalyst to speed up rate of chemical reactions in the body

what is the function of hormones?

used to carry messages around the body (insulin release by pancreas to regulate blood sugar)

what is the function of structural proteins?

physically strong (collagen used to strengthen connective tissue)

what is a mutation?

• random change in an organisms DNA that occur randomly

• mutations change the sequences of DNA bases in a gene, producing a genetic variant

what could happen if a mutation affects the shape of a protein?

• shape of the active site of an enzyme could be changed, and the substrate could no longer bind to it

• structural proteins could lose their strength

what are the 3 different types of mutations?

• insertions

• deletions

• substitutions

what does sexual reproduction involve?

• fusion of male and female gametes

• because there are 2 parents, offspring contains mixture if parents genes

what does asexual reproduction involve?

• only 1 parent

• no fusion or gametes - no mixing of chromosomes

• no genetic variation between parent and offspring (genetically identical)

what is the process of meiosis?

• before division, cell duplicates genetic information, forming 2 armed chromosomes (each arm is the exact copy of the other) and arrange themselves into pairs

• in first division chromosome pairs line up in the centre of the cell

• pairs are pulled apart so each new cell has 1 copy of each chromosome

• in second division chromosomes line up in the centre of the cell and arms of chromosomes are pulled apart

• 4 gametes are produced, each with a single set of chromosomes, each gamete is genetically different

what is the product of meiosis?

• 4 gametes

• each with a single set of chromosomes

• each gamete is genetically different (chromosomes get mixed up and each gamete gets half of them at random)