Biology- Topic 2 Flashcards
Differences between mRNA and tRNA
mRNA- found in nucleus, doesn’t carry amino acids, 3 bases called codon
tRNA- found in cytoplasm, carries amino acids, 3 bases called anticodon
Ways in which DNA can mutate
Changes in codon
Substitution Deletion Insertion Duplication Inversion
What is preimplantation genetic diagnosis?
Carried out for IVF
Screening embryos before implantation
Can identify characteristics, eye colour etc.
D- designer babies, false results
Similarities and Differences between amniocentesis and CVS
Amniocentesis- 15-20 weeks, amniotic fluid, 1% risk of miscarriage, long time for results
CVS- 11-14 weeks, less traumatic, 1-2% miscarriage, results in a few days
6 adaptations that effect rate of diffusion
surfactant, shape, elastic walls, blood supply, macrophages, squamous epithelial cells
What is Fick’s Law
rate of diffusion= SA*Conc gradient/ Thickness
Explain the properties of the cell membrane
Bi-layer- amphipathic phospholipids
Channel proteins- large & charged molecules (FD)
Glyco lipid/proteins- communication between cells
Cholesterol- make membrane rigid
Explain the fluid mosaic model
- Membrane in fluid
- Fusion of 2 cells showed inter mix of proteins
- So proteins moved and membrane is fluid
What bond is formed between amino acids?
Peptide by condensation reaction
What are secondary structure bonds?
H bonds, form alpha helix or Beta pleated
What are tertiary structure bonds?
Di-sulphide bridges between R groups
H bonds and Ionic bonds
Hydrophilic/phobic interactions
Describe the structure of collagen
Minimal tertiary structure
3 long strands of polypeptide
Coil around eachother
Fibrous
Uses of collagen in the body
Holds vessels closer to alveoli
Non-conducting, found at valves in the heart
Bond in the DNA backbone
Phosphodiester, formed by condensation reaction
3 main properties of fibrous proteins
Insoluble
Long chains
Form cross links ( strong)
