biology genetics mid topic (topic 4)

what is the shape of DNA in a eukaryotic cell

linear

what is DNA wound around

histones

what is the shape of DNA in a prokaryotic cell

circular

what is a gene

a sequence of DNA bases that code for a polypeptide or functional RNA

what do the sequence of amino acids form

primary structure of a protein

what is a triplet

3 bases that code for an amino acid

what is a genome

the complete set of genes in the cell

what is the proteome

the full range of proteins that the cell is able to produce

What are introns?

non-coding regions of DNA

What are exons?

coding regions of DNA

what are the pairs of bases in DNA

T - A

C - G

what are the pairs of bases in RNA

A - U

G - C

What are alleles?

Different forms of a gene

what are triplets in mRNA called

codons

what are triplets in tRNA called

anticodons

what is the 1st stage of protein synthesis

transcription

what is the 1st stage of transcription

DNA helicase binds to the double helix and breaks down the hydrogen bonds between the two DNA strands

what is a result of stage 1 in transcription

DNA uncoils exposing some of the bases

what occurs in stage 2 of transcription

RNA polymerase binds to the 3 prime end and travels to the 5 prime end of the DNA

what is a result of stage 2 in transcription

pre mRNA is produced from the 5 prime end

what occurs in stage 3 of transcription

complimentary RNA bases are attached to the template strand

what occurs in stage 4 of transcription

the double helix is rejoined

what occurs in stage 5 of transcription

spliceosomes bind to the RNA

what is a result of stage 5 in transcription

introns are removed from the mRNA and the mRNA enters the cytoplasm via the nuclear pore

what is stage 1 of translation

mRNA binds to a ribosome

what 2 parts are ribosomes made of

a small and a large sub unit

what happens as a result of stage 1 in translation

the ribosome attracts a tRNA molecule that binds to the first codon

what is stage 2 of translation

hydrogen bonds hold the tRNA to the mRNA

what will the first codon always code for

methionine (AUG)

what is stage 3 of translation

the ribosome attracts a second tRNA which carries an amino acid

what is the function of peptidyl transferase

form a peptide bond between the 2 amino acids and uses ATP for energy

what is stage 4 of translation

the ribosome moves on to cover the next codon

what happens as a result of stage 4 in translation

the first tRNA is released

what happens when the ribosome has fully decoded the mRNA

the amino acids in the polypeptide chain are released

what is stage 5 of translation

the chain grows until a stop codon is covered by the ribosome

what causes a gene mutation

a change in the base sequence of a chromosome

what is base substitution

one bases is replaced by another

what is base deletion

where one base is deleted which causes a frame shift to the left

What is base addition

where one base is deleted which causes a frame shift to the right

what 3 things can mutations be

harmful

beneficial

have no effect

what is step 1 in natural selection

variation in species

what is step 2 in natural selection

overproduction of offspring

what is step 3 in natural selection

Survival of organisms with

advantageous characteristics

what is step 4 in natural selection

Advantageous characteristics passed on to offspring

what is step 5 in natural selection

Gradual genetic change over time

what happens to the conditions in directional section

the environmental conditions change

what happens to the conditions in stabalising section

the environmental condition stay stable

What occurs in directional selection?

a random mutation occurs which is advantageous

what happens to the population that don't have the advantageous mutation in directional selection

the are eliminated

what happens to the population that have the advantageous mutation in directional selection

the survive and the population increases as they reproduce

What occurs in stabalising selection?

individuals with phenotypes closest to the mean survive

in stabalising selection what happens to the extreme phenotypes

they are eliminated

what is the result of stabalilsing selection

the extreme phenotypes die and the phenotypes closer to the mean reproduce

What occurs in the first stage of meiosis

DNA duplicates

What occurs in the second stage meiosis

Cell splits

What occurs in the third stage of meiosis

Cell splits a second time forming haploid cell

what is the founder effect

a type of genetic bottle neck

a few organisms from a population start a new colony due to migration

what does lots of alleles mean

high biodiversity

what is the example of directional selection

antibiotic resistance

what is the advantageous characteristic in directional selection

resistance to antibiotics in bacteria

what is the example for stabilising selection

human birth weight

what is the advantageous characteristic in stabilising selection

being closer to mean birth weight

name 4 technique to prevent contamination

disinfect worksurface

don’t place contaminated utensils on work surface (into beaker)

use sterile equipment

flame the neck of the bottle before and after use

what is the order a classification

domain

kingdom

phylum

class

order

family

genus

species

what is the acronym for classification

Dear King Philip Came Over For Good Soup

what is the 1st part of the binomial naming system

genus

what is the 2nd part of the binomial naming system

species

define species

a group of similar organisms that can produce fertile offspring

describe courtship

attracting a mate of the right species

what is the top number in the index of diversity

total number of all organisms within all species

what is the bottom number in the index of diversity

total number of all organisms within one species