Topic 2 Flashcards
How has the lungs adapted for gas exchange?
-Lots of alveoli, creates larger S.A to Volume for diffusion
-Alveoli and capillary endotheliums are 1 cell thick
-Good supply of blood
-Breathing in and out, refresh air -> maintain concentration gradient
Structure of a phospholipid + its properties
-Phosphate head, attracts water
-2x Fatty Acid Tails, repels water
What is faciliated diffusion?
-Diffusion for larger and charged particles
-Across a membrane, down the concentration gradient
-Passive process
Explain active transport
-Movement of substances against a concentration gradient
-A molecule attaches to the carrier protein
-It changes shape and moves the molecule across a membrane, releasing it
-Uses ATP as energy, produced by respiration
-ATP is hydrolysed for use
Explain endocytosis
-A cell membrane can surround substance
-Membrane pinches off in the inner, forming a vesicle
-Uses ATP for energy, accessed by hydrolysis
Explain exocytosis
-Vesicles containing substance pinch off sacks of the golgi apparatus to the cell membrane
-Vesicle fuses into the membrane, releasing contents out of the C.M
Structure of a protein
-Made from mono/polymers of amino acids
-Which join together through a condensation reaction
-Forming peptide bonds
Explain globular protein structure
-Globular proteins are round, compact
-Made of multiple polypeptide chains
-Coiled up, hydrophillic parts on outside and hydrophobic on inside
-Protein is soluble, easy for transportation
-E.g Haemoglobin
Explain fibrous 3d protein structure
-Fibrous proteins are made of long, insoluble polypeptide chains
-Polypeptide chains held together by many bonds (disulfide, H)
-Strong and long, can be found in supportive tissues
-E.g Collagen
Explain enzymes
-Is a biological catalyst
-Is a protein
-Have an active site, which has specific shape where substrate molecules bind to
-Lower the activation energy of a reaction
Explain RNA
-RNA is similar to DNA
-RNA transfers genetic information from DNA to ribosomes
-Its nucleotide has a ribose sugar
-Are polymers of mononucleotides
Explain nucleotides
-Pentose Sugar (5C Sugar)
-Nitrogen-containing organic base
-Phosphate group
-Make up DNA and RNA
-Phosphodiester bonding
Explain DNA
-DNA stores genetic information
-Are polymers of mononucleotides
-Its nucleotide has a deoxyribose sugar
-TAGC bases
Explain mRNA
-Messenger RNA is made in the nucleus, during transcription
-3 adjacent bases = codon
-Carries genetic code from DNA in nucleus to cytoplasm, for translation into a protein
Explain tRNA
-Transfer RNA is in the cytoplasm
-Has amino acid binding site
-Has a sequence of 3 bases, a complementary anticodon
-Carries amino acids to ribosomes during translation
Explain Non-Overlapping and Degenerate code
-N.O: each base triplet (codon) is read in sequence, no codons share bases
-Dg: amino acids are able to be coded for by more than one codon
Explain transcription
-RNA polymerase attaches to DNA double helix at beginning
-DNA Helicase leads to H bonds breaking, strands seperate, DNA Helix unwinds
-One strand is used as a template
-RNA polymerase lines up free floating RNA nucleotides to complementary base pair with the template
-RNA polymerase joins the original strands together, leaving the new mRNA strand
-H Bonds reform once RNA polymerase has passed
-Stops at a stop codon
-mRNA moves out through a nuclear pore, to a ribosome in the cytoplasm for translation
Explain translation
-mRNA attaches to ribosome, and tRNA, in cytoplasm
-tRNA with complementary anticodon pairs to the mRNA
-A 2nd tRNA does the same, and this repeats
-Amino acids on the tRNA molecule are joined via a peptide bond, prior tRNA leaves
-Polypeptide moves away from the ribosome when a stop codon is reached
Explain semi-conservative replication
-DNA helicase breaks H bonds between bases on the strands, unwinding it
-Both strands act as a template strand, free floating DNA nucleotides begin to complementary base pair.
-Condensation reactions occur, joining the nucleotides of strands together catalysed by DNA polymerase
-Hydrogen bonds form between bases
-Ultimately two DNA molecules have formed, both have an original and new strand
Name the 5 types of mutation
-Substituion
-Deletion
-Insertion
-Duplication
-Inversion
What does a mutation lead to?
-Order of DNA bases change
-This changes order of amino acids
-Changes primary structure, and it’s final 3D shape, protein may not function
-Mutation of a gene can lead to a genetic disorder e.g CF
Explain Cystic Fibrosis and its cause
-Inherited disorder affecting respiratory, digestive and reproductive systems
-Caused by recessive allele (f)
-Person gets it if they are homozygous with the allele (ff)
-Caused by a mutation in gene for CFTR protein
Explain effects of cystic fibrosis
-Caused by a mutation in gene for CFTR protein
-CFTR is a channel protein which transports Cl ions out of cells into mucus
-Causes water to move into mucus via osmosis, making it watery
-Mutant CFTR makes it less efficient at Cl movement so less water moves out and into mucus via osmosis
-Mucus becomes thick and sticky, affecting body systems
State 3 uses of genetic screening
-Identification of carriers
–>Done before having children, life insurance/companies use data (genetic discrimation)
-Preimplanation Genetic Diagnosis
-Prenatal Testing
