2.2 DNA Flashcards
What are the four bases?
Cytosine triple bonds to guanine
Adenine double bonds to thymine
What is the function of DNA?
Stable and can passed from generation to generation without change
Large molecule carries a vast amount of data
Genetic material is protected by the backbone
Hydrogen bonds allow separation in replication
What is the triplet code?
Groups of three bases of read in a triplet and code for one of 20 amino acids
There are also in introns code for stop and start codes
What are chromosomes?
They are present in eukaryotes and are only visible when a cell is dividing
They occur in homologous pairs
What is in allele?
Genes are DNA which contain coded Information. These exist in multiple forms and Alllele
What are the stages of meiosis?
Interphase
G1 – proteins from cell organelles are synthesised
S1 – DNA is replicated
G2 –organelle grow and energy stores increase
Prophase – chromatids cross and swap
Metaphase – chromosomes line up the Equator
Anaphase – homologous chromosomes pulled apart
Telophase- to diploids with individual membranes
Prophase 2- chromosomes stationary. Spindle fibres form
Metaphase 2- chromosomes line up the Equator
Anaphase 2 – spindle fibres pull chromatids apart
Telophase 2- 4 different haploid
What is selective breeding?
Choosing organisms with certain traits so that they are shown by the offspring
What is the founder affect?
Removing a few individuals from a population to colonise a new region
What are genetic bottlenecks?
Dramatic drop in the numbers reduce the alleles
Why is genetic diversity important?
Think cows! Increase milk yield Decrease disease Increase health Increase lifespan Increase fertility
What is DNA made out of?
Phosphate group
Deoxyribose sugar
Organic base
What is a gene? I
section of DNA which codes for a protein
