DNA AND RNA

Structure of DNA WHAT IT STANDS FOR

Deoxyribonucleic acid. in the nucleus mitochondria or chloroplast. can fit into nucleus and coil and fold two strands

4 DNA bases

Adenine thymine guanine cytosine

what is meant by complimentary base pair and which match with what

bases that match with one another. Adenine thymine guanine cytosine

where can non nuclear DNA be found

mitochondria or chloroplast

write a short note on complimentary base pairs

bases joined by hydrogen bonds. cytosine with guanine adenine with thymine in DNA but Adenine and uracil in RNA

DNA SHAPE

Double helix

what is a gene

section of dna that has the code for production of protein

how many common amino acids are used in production of proteins

20

how many amino acids are needed to form a protein

over 200

what is a genetic code

a sequence of three bases(codon) that represent a code for an amino acid

what is a codon orr triplet

sequence of 3 bases that represent a code for an amino acid

example of a colon.

CAA Valine and CGA alanine

what is non coding DNA and other name

doesn’t have genetic instruction for the formation of a protein. junk DNA

nucleotide

units DNA is made up of

structure of nucleotide

phosphate nitrogen base and sugar(deoxyribose or ribose)

which part of a nucleoitide can vary

the nitrogren bases

polynucleotide

many nucleotides tied together

what holds bases together

hydrogen bonds. adenine and thymine form 2 weak bonds guanine and cytosine form three bonds

purines

adenine and guanine (double ringed molecules)

pyrimidine

thymine cytosine. single ringed molecules

what scientists discovered shape structure DNA

crick and watson

what does RNA stand for and components.

Ribonucleic acid uracil instead of thymine. single stranded. pair up with DNA found in nucleus cytoplasm and ribosome

2 nucleic acids

DNA and RNA

DNA replication why

occurs so there is an exact copy of the DNA for mitosis to occurs. during interphase.

mitosis

one cell divides into two identical daughter cells

how does DNA replication occur

enzymes break hydrogen bond between base pairs. doubble helix unwinds. other DNA bases enter the nucleus and join with exposed strand. two new strands formed identical to original stand

what enzyme is used to make new strands DNA

DNA polymerase

DNA profiling

method of making a unique pattern of bands from the DNA of a person. used to tell the difference between different DNA

applications of DNA profiles

solving crimes. maternity tests.

who has indentical DNA profiles and why

identical twins. diploid zygote cell divides by mitosis completely splits.

method of DNA profiling

DNA released by breaking down cell. cut into fragments using restriction enzymes. fraggments are seperated based on size.seperated by process called gel electrophoresis, patterns compared analysed

gel electrophoresis

how fragments of DNA are seperated. electric

genetic screening

testing DNA for the presence or absensce of altered gene

what can genes be altered by

mutations. altered genes dont have correct code for production of protein.

examples of genetic disorders caused by altered genes

albinism cystic fibrosis

where is genetic screening used

adult screening. tells them if their children will have genetic diseases or if they are carries.

foetal screening (unborn baby)

child can be tested for genetic disorders

what ethical issues do genetic screening bring

mothers may terminate pregnancy if unborn child has disorder

protein synthesis (making of a protein) where what type reaction and steps.

anabolic in ribosome transcription and translation

three types of RNA involved

Messenger RNA transfer RNA and ribosomal rna

transcription steps

enzymes start unwind the DNA double helix in nucleus. complimentary RNA base join the exposed DNA RNA polymerase joins RNA bases to make MRNA.

what does each mRNA strand

a start codon series of codons represent different amino acids and stop codon(start and stop not involved in protein production)

transcription definition

Making of MrNa fron DNA

translation definition

making of protein depending on the mRNA code

what does rRna do in translation

holds mRNA in place

tRNA where found and what in contains

cytoplasm contains an anticodon to attached to an amino acid

what is an anticodon

sequence of three bases on tRNA

function of mRNA

gets code from DNA in nucleus carries code to the ribosome

rRNA

found in ribosome. binds the mRNA in place in ribosome

tRNA

carries amino acid to ribosome binds with mRNA and places amino acid in sequence

what happens if the genetic code isnn’t corrected

won’t form the correct protein may result genetic disorder (e.g cystic fibrosis)

how does a protein become functionable

it folds

describe steps involved translation

mRna enters ribosome rRNA holds mRNA in place. tRNA carries amino acid into ribosome. tRna binds with the mRNA amino acids placed in correct sequence new protein folds

during protein synthesis do all proteins have the same shape / or structure

some havbe folded(globular) e.g enzymes. some have little folding(fibrous) eg keratin

Alleles

different (alternative) forms of same gene

Locus

position of gene on a chromosome.

Dominant

this allele prevents the recessive allele from working

Recessive

allele is prevented from working (being expressed) by dominant allele.

Genotype

the genetic make up of an organism

Phenotype

the physical make up (appearance) of an organism when gene is physically expressed.

• Homozygous

the two alleles are the same (or when identical alleles are present)

Heterozygous

means that the alleles are different.

Progeny

refers to the offspring produced

species

group of similar organisms that are able to reproduce together to make fertile offspring.

variation

differences between members of the same species

types of variation

inherited and acquired variation

what is acquired variation

not inherited but learnt through life

what is inherited variation

passed down from one generation to the next

causes of inherited variation

mutations and sexual reproduction(meoisis)

what is a mutation

change in the amount or structure of DNA. correct protein no longer produced

what happens if a mutation survive

passed on to the next gen and leads to evolution

mutagen

agemts that are cause of mutation

type of mutagens

ultraviolet radiation tobacco smoke

type of mutation

gene and chromosomal

gene mutation

changed in a single gene eg cystic fibrosis or sickle cell anaemia

evolution

occurs over long periods of time and which living things change genetically

scientists who viewed evolution

charles darwin alfred wallace

observation and conclusion natural selection

overbreeding population numbers remain constant competition and natural selection