All Unit 1 Higher Biology

genomic sequencing

Determining the sequence of nucleotide bases for individual genes and entire genomes

genomics

the study of genomes

Bioinformatics

use of computer databases to organize and analyze biological data

Phylogenetics

the analysis of evolutionary, or ancestral, relationships

phylogentic tree

Evolutionary history of a group of organisms represented in a branching diagram; represents hypothesis about evolutionary relationships

molecular clock

Model that uses DNA comparisons to estimate the length of time that two species have been evolving independently

3 domains of life

Bacteria, Archaea, Eukarotes

Pharmacogenetics

Area of pharmacology that examines the role of genetics in drug response.

personal genomics

the branch of genomics focused on sequencing individual genomes

Exons

Coding segments of DNA.

Introns

Sequence of DNA that is not involved in coding for a protein

tRNA (transfer RNA)

type of RNA that carries amino acids to the ribosome

mRNA

messenger RNA carries a copy of the gene from the nucleus to the ribosome

rRNA

ribosomal RNA; type of RNA that makes up part of the ribosome

codon

3 base code in DNA or RNA

anti-condon

A sequence of three bases of a tRNA molecule that pairs with the complementary three-nucleotide codon of an mRNA molecule during protein synthesis.

The difference between DNA and RNA

DNA has deoxyribose, thymine, and is double stranded

RNA is made up of ribose, uracil, and is single stranded

RNA splicing

The process of intron removal from the primary transcript.

Transcription

synthesis of an RNA molecule from a DNA template

Translation

Process by which mRNA is decoded and a protein is produced

protein structure

Long chains of amino acids joined to each other by peptide bonds

Phyenotype

the appearance due to the order of genes

tRNA

Single strand of RNA which folds due to base pairing to form this unusual shape. It has a triplet anti-codon site and an attachment site for a specific amino acid.

Uracil

replaces thymine in RNA

Non-coding regions

introns

Exons are spliced to form

Mature mRNA

Primary transcription

The initial rna transcript with itrons and exons

Peptide bonds

Bonds between amino acids

start codon

Aug

stop codon

codon that signals to ribosomes to stop translation

alternative splicing

one gene can code for more than one protein

Double helix

The shape of a DNA molecule

hydrogen bonds

Weak bonds that connect the two strands together at the base pairings.

3'

the three prime end (the bottom)

5'

the five prime end (at the top)

Sugar phosphate

Make up the backbone of DNA or RNA.

Deoxyribose

A five-carbon sugar that is a component of DNA nucleotides

Nuclotide

the basic unit of DNA

Adinine Pairs With

Thymine

Thymine pairs with

Adenine

Guanine pairs with

Cytosine

Cytosine pairs with

Guanine

Genotype

genetic makeup of an organism

Prokaryote

A unicellular organism that lacks a nucleus and membrane bound organelles

Eukaryote

A cell that contains a nucleus and membrane bound organelles

linear chromosomes

Eukaryotes

circular chromosomes

prokaryotes

How many strands does DNA have?

2

PCR (polymerase chain reaction)

is used to copy and amplify minute quantities of DNA

Stage 1

DNA is unwound and unzipped, hydrogen bonds are broken

Stage 2 (leading strand)

a primer is added to the 3' end and DNA polymerase will add the loose DNA nucleotides using complementary base pairing.

Stage 2 (lagging strand)

Lagging strand is synthesised in fragments. Nucleotides cannot be added to the phosphate (5') end because DNA polymerase can only add DNA nucleotides in a 5' to 3' direction. The lagging strand is therefore synthesised in fragments. The fragments are then sealed together by an enzyme called ligase.

Stage 3

2 new strands are made

1st stage of PCR

DNA heated to between 92 and 98°C- to denature the DNA and separate the two strands.

2nd stage of PCR

DNA cooled to between 50 and 65°C - to allow primers to bind to target DNA sequences.

3rd stage of PCR

Complementary primers added - which are complementary to the target sequences at the two ends of the region to be amplified.

4th stage of PCR

Heated to betweeen 70 and 80°C -tolerant DNA polymerase added - which replicates the region of DNA to be amplified. Two strands are formed.

5th stage of PCR

Repeated cycles of heating and cooling amplify the target region of DNA.

Uses for PCR

solve crimes, settle paternity suits and diagnose genetic disorders.

DNA polymerase

Enzyme in DNA replication that binds individual nucleotides to produce a DNA molecule

Nucleotide

1 set of dna

Primer

A short segment of DNA that acts as the starting point for a new strand

Ligase

An enzyme that connects two fragments of DNA to make a single fragment

Lagging strand

Is discontinus

gel electrophoresis

separates DNA fragments by size

cellular differentiation

the process by which a cell expresses certain genes to produce PROTEINS characteristic for that type of cell

stem cells

undifferentiated cells that can divide and differentiate

embryonic stem cells

embryonic cells, which can develop into any type of body cell and are pluripotent

tissue stem cells

stem cells from tissue that divide and differentiate to become cells of that tissue and are multipotent

uses of tissue stem cells

Growth, repair and renewal of the cells found in that tissue

ethical issues in embryonic stem cells

involves destruction of embryos

Therapeutic uses of stem cells

the repair of damaged or diseased organs or tissues

research uses for stem cells

study how diseases develop or being used for drug testing

meristems

Meristems are regions of unspecialised cells in plants that can divide (self-renew) and/or differentiate.

Apical meristems

found in the Root Tip & Shoot Tip, These increase in length/height.

Lateral meristems

A meristem that thickens the roots and shoots of woody plants.

Genome

entire hereditary information encoded in DNA

Genome is made up of

Genes and other DNA sequences that do not code for proteins

genes

DNA sequences that code for protein

Non-coding sequences can either

regulate transcription or transcribed and not translated

transcribed but not translated

trna and Rrna

Evoultion

changes in organisms over generations as a result of variation in the populations genome

natural selection

non-random process that results in frequent of DNA sequences that increases survival and the non random reduction in deleterious sequences

stabilising selection

the average phenotype is selected

disrupive selection

the extreme versions of phenotypes are favoured

directional selection

one extreme phenotype is favored

vertical gene transfer

transfer of genes from an organism to its offspring

horizontal gene transfer

transfer of genes between cells of the same generation

what gene transfer is more rapid

horizontal gene transfer

speciation

the evolutionary process by which new species are formed as a result of isolation mutations and selection

allopatric speciation

the process of speciation that occurs with geographic isolation

sympatric speciation

The formation of new species in populations that live in the same geographic area (ecological or behavioural)

Evoultion

changes in organisms over generations as a result of variation in the populations genome

natural selection

non-random process that results in frequent of DNA sequences that increases survival and the non random reduction in deleterious sequences

stabilising selection

the average phenotype is selected

disrupive selection

the extreme versions of phenotypes are favoured

directional selection

one extreme phenotype is favored

vertical gene transfer

transfer of genes from an organism to its offspring

horizontal gene transfer

transfer of genes between cells of the same generation