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CfE Higher Biology Unit 1

Terms in this set (88)

Adenine (A)
base that pairs with thymine in DNA (and uracil in RNA)
Antiparallel
parallel strands in DNA running in opposite directions
Base
nitrogenous substance that is a component of a DNA nucleotide
Chloroplast
organelle in which the chemical reactions of photosynthesis occur
Chromosome
structure that contains the genetic material of an organism encoded into DNA
Cytosine (C)
base that pairs with guanine in DNA
Deoxyribose
pentose sugar that is a component of a DNA nucleotide
DNA
deoxyribonucleic acid; a molecule that holds the genetic code in living organisms
Double helix
three dimentional shape of a DNA molecule
Eukaryotic
cell with a discrete nucleus
Guanine (G)
base that pairs with cytosine in DNA
Hydrogen bond
weak chemical link joining complementary base pairs in DNA
Mitochondria
cell organelles in which the aerobic stages of respiration occur
Nucleotide
component of DNA consisting of a deoxyribose sugar, a phosphate group and a base
Phosphate
component of a DNA nucleotide that is derived from phosphoric acid
Plasmid
circular loop of genetic material found in prokaryotic organisms and some yeasts
Protein
large molecule made up from a chain of amino acids linked my peptide bonds
sugar-phosphate backbone
strongly boned strand of DNA
Thymine (T)
base that pairs with adenine in DNA
3'-5'
strand of nucleic acid running from a sugar to a phosphate
DNA polymerase
enzyme that adds free complementary DNA nucleotides during replication of DNA
Heat-tolerant DNA polymerase
enzyme from hot-springs bacteria, used in PCR
Lagging strand
DNA strand that is replicated in fragments
Lead strand
DNA strand that is replicated continuously
Ligase
enzyme that joins DNA fragments to make the lagging strand
Polymerase chain reaction (PCR)
method of amplifying sequences of DNA in vitro
Primer
short complementary strand of DNA
Replication
formation of identical copies of DNA molecules
Template strand
DNA strand on which a complementary copy is made
Amino acid
unit of polypeptide structure
Anticodon
sequence of three bases on tRNA that specifies an amino acid
Exon
sequence of DNA that codes for a protein
Gene expression
transcription and translation
Intron
non-coding sequence of DNA
Mature messenger RNA (mRNA)
carries a copy of the DNA code to a ribosome
Molecular interactions
various chemical links joining amino acids and giving protein molecules their shapes
Peptide bonds
strong chemical links in the primary structure of polypeptides
Differentiation
changes to cells involving switching on certain genes and switching off others
Embryonic stem cells
stem cell from an embryo that can divide and become any type of a cell
Meristem
region in a plant in which mitosis occurs
Stem cell
cell that can divide and then differentiate in animals
Therapeutic
used as part of medical therapy
Tissue (adult) stem cells
stem cells from tissue that can divide and differentiate to become cells of that tissue
Phenotype
outward appearance of an organism
Polypeptide
short strand of amino acids
Post-translational modification
changes made to polypeptides following translation
Primary transcript
molecule made with DNA is transcribed
Ribosomal RNA (rRNA)
type of RNA that makes up ribosomes
Ribosome
site of protein synthesis; composed of rRNA and protein
RNA
ribonucleic acid, which occurs in several forms in cells
RNA polymerase
enzyme involved in synthesis of primary transcripts from DNA
RNA splicing
joining of exons following the removal of introns form a primary transcript
Transcription
copying of DNA sequence to make a primary transcript
Transfer RNA (tRNA)
transfers specific amino acids to the mRNA on the ribosomes
Translation
production of a polypeptide using sequences of mRNA
Uracil
RNA base not found in DNA
Deletion of genes
chromosome mutation in which a sequence of genes in lost from a chromosome
Deletion of nucleotides
single gene mutation involving removal of a nucleotide from a sequence
Duplication
chromosome mutation in which a sequence of genes repeated on a chromosome
Genome
total genetic material present in an organism
Insertion
single gene mutation in which an additional nucleotide is placed into a sequence
Inversion
chromosome mutation in which a set of genes rotates through 180 degrees
Mutations
random changes to DNA sequences
Non-coding sequence
DNA sequence that does not encode protein
Polyploidy
possession of extra sets of chromosomes
Splice-site mutation
mutation at a point where coding and non-coding regions meet in a section of DNA
Substitution
single gene mutation in which one nucleotide is replaced by another
Translocation
mutation in which part of a chromosome becomes attached to another
Allopatric speciation
speciation in which gene flow is prevented by a geographical barrier
Behavioural barrier
barrier to gene flow caused by behavioural differences between individuals
Biological species
group of similar organisms interbreeding to produce fertile offspring
Directional selection
natural selection that tends to favour an extreme value of a varied characteristic
Disruptive selection
natural selection that favours two different values of a varied characteristic
Ecological barrier
barrier to gene flow caused by ecological preference differences between individuals
Evolution
change in the genetic constitution of a population over time caused by natural selection
Genetic drift
random changes to DNA sequences
Geographical barrier
physical barrier to gene flow, such as a mountain or river
Horizontal inheritance
inheritance of genetic material within a generation
Hybrid zone
region in which frequent interbreeding between two species occur
Natural selection
process that ensures survival of the fittest
Sexual selection
natural selection of characteristics that increase reproductive success
Speciation
evolutionary process by which new species are formed
Stabilising selection
natural selection that favours a middle value of a varied characteristics
Sympatric speciation
speciation in which gene flow is prevented by ecological or reproductive barriers
Vertical inheritance
Inheritance of genetic material from parents to offspring
Bioinformatics
use of computers and statistics in analysis of amino acid or nucleotide base sequences
Personalised medicine
possible future development in which treatment is based on an individual's genome
Phylogenetics
study of evolutionary relatedness of species
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