dna n inheritance

proteins dna strands coil around

dna remains intact, when the coiled chromatins become even more tightly coiled (chromosomes) structure of DNA is twisted into a double helix

each phosphate group and sugar molecule with a nitrogenous base is a nucleotide.

sections of the DNA. molecule that contain the genetic code (stored information + codes for activities)

a single molecule that can join together to form a larger molecule made up of nucleotides joined together

guanine cytosine adenine thymine

-DNA is a polymer of mononucleotides- join together between the phosphate of one nucleotide and the sugar (deoxyribose) group of the adjoining nucleotide.

• this occurs before cell division • happens during interphase of mitosis and meiosis • an enzyme (helicase) causes the 2 strands of DNA to split • free roaming nucleotides in the nucleus are attracted to their complimentary base pairs • the string sugar phosphate backbone is rejoined by DNA polymerase • each new DNA molecules consists of 1 parent strand and 1 new one • an enzyme rewinds the double helix

long chains of amino acids • haemoglobin • actin + myosin • albumin • amylase • collagen

• messenger ribonucleic acid (RNA) • DNA that contains genes are too big to leave the nucleus pores, so a copy of the gene is made instead in the form of mRNA • Uracil is used instead of thymine

• the process in which a copy of DNA is made (mRNA) • mRNA is single strand • Helicase unzips DNA exposing the nitrogen base code • RNA polymerase works along the template strand and adds new nucleotides; U to A, A to T, C to G and G to C • mRNA leaves nucleus and carries genetic message to the ribosomes which are the protein-synthesising structures of the cell

• process in which genetic code carried by mRNA directs ribosomes to connected amino acids to eachother to produce proteins • proteins assembled by ribosomes which line the ER or float around cytosol • individual molecules of transfer RNA have a sequence of 3 nucleotides (anticodon) thag bind to the complimentary triplet (codon) in mRNA • each anticodon bind to a specific amino acid

-a set of chemical compounds and proteins that attach to DNA that act like switches and markers that influence gene expression

• a change in the phenotype without changing the genotype - life style changes alter how our genes vegans without actually changing genetic makeup eg smoking

when a ACETYL group (COCH3) attaches to a histone, causing histone to spread, making it easier for DNA to be read by the RNA polymerase, ENHANCES gene expression

when a methyl group (CH3) attaches to cytosine • CpG • prevents RNA polymerase from reading the gene • inhibits gene expression— turns the gene off

alternative forms of the same gene

a blend of the two heterozygous alleles giving rise to a third phenotype

a heterozygous individual expressed both simultaneously without any blending

• recessive • abnormal haemoglobin production = anaemia • frequent blood transfusions due to excess build up of iron • frequent in mediterranean countries

• recessive, autosomal disease • common in areas of a malaria endemic • crescent shaped blood cells, reduces amount of oxygen can be carried • causes RBC to stick together and block up blood vessels • usually fatal

• autosomal recessive disorder • inability to metabolise lipids due to a missing enzyme • accumulation of fatty substances in the nervous system and brain • affects sight, hearing, movement and mental development. death in early childhood • jewish heritage and french canadian/cajun heritage

• random assortment during meiosis • crossing over during meiosis • nondisjunction during meiosis • random fertilisation

• during the first meiosis division, homologous pairs are separated at random • chromosomes move to opposite poles