T2: Genes And Health Flashcards
Describe the lung structure
Trachea
Bronchi
Bronchioles
Alveoili
Adaptations of the trachea
Ciliate epithelium
Produce mucus to trap pathogens
Sweeps away pathogens
What is epithelial tissue
Lines surfaces in your body
Name and describe 3 types of epithelial tissue
Columnar epithelium: apical membrane, columnar epithelium cells, basement membrane, extra cellular matrix
Squamous epithelium: apical membrane, squamous epithelium cells, basement membrane, extra cellular matrix
Ciliated epithelium: ciliated epithelium cells, goblet cells, basement membrane, extra cellular matrix
What are the alveoli and how are they adapted to their unctions
Why do boys steal mums veal
Site of gas exchange of CO2 and O2
Short dd (squamous epithelium)
Conc grad (good bs flow, ventilation)
Large SA
Moist lining (gases can dissolve/diffuse)
Warm (increase ROD)
Fick’s law
ROD = (SA x conc diff) / dd
ROD = k x SA
ROD = k x conc grad
ROD = k / dd
Structure of amino acid
Amine group (NH2) R group (CHR) carboxylic acid group (COOH)
Structure of amino acid dissolved in water
Amino acid
Carboxylic acid loses an H
H goes to amine group
Amine group = pos charg
Carboxylic acid group = neg charge
How are polypeptides formed
Peptide bonds between AG and CAG
CAG loses OH
AG loses H
Condensation reaction
Water formed
(Reverse = hydrolysis)
What is an R group
Group that gives different chemical characteristics
2 types
Charged/ionic R group 2 examples
Aspartic acid
Lysine
Polar R group
Not charged
Interacts with water
Forms hydrogen bonds
Serine
Hydrophobic R group
Don’t bond with water
Hydrocarbon side chains
Valine
Phenylalanine
Describe the primary structure of an polypeptide
Sequence of amino AAs
Peptide bonds
Start = N terminal, AG
End = C terminal CAG
Describe the secondary structure of an polypeptide
3D structure
Hydrogen bonds between backbone of AA chain (polypeptide excluding RG)
Alpha: helix, RG point out, HB between C=O and N=H of different AAs
Beta: folded sheet, RG alternate in direction, HB between C=O and N=H of adjacent strand AAs
Describe the tertiary structure of an polypeptide
Disulphide bridges: cov bonds between 2 s
Charged/salt bridges/ionic: pos charged RG
Polar: RG move outside, hydrophilic, can form HB with each other
Hydrophobic: R groups move to centre, away from water
Describe the quaternary structure of an polypeptide
Multiple folded polypeptides/groups
Same interactions as tertiary structure
Name two variables that lead to denaturing proteins
Temperature
Ph
How does temperature cause denaturing
Polypeptide moves more as temp increases
Threshold temp, ionic/hydrogen/hydrophobic bonds break
Elongates protein
How does pH cause denaturing
Charged AA lose/gain charge
Pos charged AA: acidic = removes charge
Neg charged AA: alkali = removes charge
Name two types of proteins
Fibrous
Globular
Describe a fibrous proteins and give an example
Insoluble in water
3 long chains
Overlap at ends
Structural/mechanical function (muscle)
Collagen
Describe a globular proteins and give an example
Soluble in water
Enzymes, carrier/signalling molecules
Individual proteins not long structures
Haemoglobin
Collagen
Repeating pattern (fly, pro, pro)
Glycine: small RG, closely packed
Proline: limits rotation
Helix
Haemoglobin
4 subunits, can carry 4 oxygen molecules
Iron core
Globular
Transports oxygen in RBCs
Name and describe the 5 parts of a phospholipids
Phosphate: hydrophilic, polar
Glycerol: hydrophilic
Fatty acids: hydrophobic
Ester bond
Phosphoester bond
Describe the fluid mosaic structure
Bilayer of phospholipids, head face out, tails face in
Glycoproteins, peripheral, integral proteins
Cholesterol
Partially permeable
Name 3 factors that effect the fluidity of the cell membrane
No. Cholesterol, fill tail gaps, increase fluidity
Temperature, more KE, more fluidity
No. Unsaturated fatty acids, more fluidity
Describe un/saturated fatty acids and how they effect the cell membrane
Saturated, single bond between Cs, straight Thais, easily stacked, less fluid
Unsaturated, double bonds between Cs, kinked tails, not easily stacked, more fluid
Describe how different types of molecules pass through the cell membrane
Small, non-polar, phospholipid gaps
Large, polar, channel/carrier proteins
Describe scientific evidence for the fluid mosaic cell membrane structure
Gorter and Grendel
Bilayer, SA RBC vs lipid 1:2
Davson and Davelli
Layered proteins, electron micrograph, ligh band
Robertson
Trilaminar, polypeptide, bilayer, polysaccharide, electron micrograph, non uniform
Singer and Nicolson
Fluid mosaic, proteins within bilayer, FRAP, can move
Name 6 forms of movement
Diffusion
Facilitated diffusion
Osmosis
Active transport
Endocytosis
Exocytosis
Describe Diffusion
New movement of particles from high to low concentration
Reaches equilibrium
Passive
Hydrophobic, small, uncharged particles
Describe Facilitated diffusion
Transport/channel/carrier proteins
High to low concentration
Reaches equilibrium
Passive
Hydrophilic, large, charged particles
Describe osmosis
Net movement of water from high to low water potential through a partially permeable membrane
Describe active transport
carrier proteins/pumps
Na/K nervous control
Low to high concentration
Needs ATP/energy
Describe endocytosis
Bulk transport, taking material IN
Memebrahne folds around particle
Forms vacuole, digest food
Needs energy
Exocytosis
Bulk transport
Takes material OUT
Vesicles fuse with cell surface membrane
Release contents
Requires energy
Describe the mononucleotides
Phosphate
Pentose sugar (deoxy/ribose)
Nitrogenous base (pyrimidine/purine)
Anti parrallel link
Nitrogenous bases
Pyrimidine, 1 nitrogenous ring, C/T
Purine, 2 nitrogenous ring, A/G
C - G, 3 H bonds, stronger
T - A, 2 H bonds, weaker
Describe the DNA structure
Deoxyribonucleic acid
Double helix
Made of nucleotides
Hydrogen bonding between complimentary base pairs
Genotype
Alleles that an organism has
homozygous
Both alleles for one gene are the same
Heterozygous
Alleles for one gene are different
Recessive
Both alleles needed to be expressed in the phenotype
Phenotype
What organism looks like
Dominant
If allele is present it will always be expressed in he phenotype
Gene
Sequence of bases on a DNA molecule that codes for the amino acid sequence of a specific polypeptide chain
RNA
Copy of one strand of DNA
Codons
3 bases grouped together
64 codons
Non overlapping
Degenerate (multiple encode same amino acid)
20 amino acids
Stop/start codons, signal end/strt of protein chain
Describe protein synthesis generally
Transcription: DNA base pairs -> mRNA
Translation: tRNA + mRNA -> polypeptide
Transcription
Nucleus
RNA polymerase attaches to DNA in front of non coding gene
Enzyme unzips DNA strand (break H bonds)
Enzyme adds comp RNA nucleotides to antisense
DNA strands join back
mRNA leaves through nuclear pore
Translation
Ribosomes
Bases read in codons
Codons encode aa
Anticodons on aa comp mRNA codons
Ribosomes move along mRNA
Join aa (peptide bonds) -> Polypetide
Folds -> protein
Describe mutation
Change in genetic base sequence
Variation
Most have no effect on phenotype
Some make alleles (change protein shape/function)
Causes of mutation
Random
Cell division
Ionising radiation
Carcinogens
CFTR role
Controls mucus viscosity
Epithelial cells
Airway/reproductive/digestive systems
Too sticky: cilia cant beat/remove mucus, clogs airway
Too runny: mucus floods airway
Genome
All the genes in an individual
Allele
Different forms of the same gene
Describe DNA replication
Growth and repair
Mitosis/cell division
Exact copy of genetic material
Describe the DNA replication process
DNA helicase breaks H bonds between strands
Free nucleotides bind, comp bases
DNA polymerase + nucleotides -> sugar phosphate backbone, phosphoester bond, condensation
2 new DNA molecules, one OG strand, one new
Semi conservative
DNA rewound by enzyme
DNA conservative theory
Complete DNA molecule
Template for daughter strand
Assembled only for nucleotides
Parent molecule unchanged
DNA fragmentary/dispersive
Parent strand fragments -> nucleotides
Old and new nucleotides make strand
Practical evidence for semi-conservative theory
E coli bacteria
Different DNA densities
Centrifuge
Nitrogen -> bacteria -> new DNA
N15, low line
N14, middle line
Conservative disproved (2 lines high/low)
N14, again, 2 lines middle/high
Fragmentary: disproved, middle line
Semi conservative: proved
CTFR protein function
Controls mucus viscosity
Lines epithelial cells
Airway/digestive/reproductive
Maintain salt/water balance
Uses ion channel
Epithelial cell membrane general structure
2 carrier proteins/pumps
Active transport Na+,Cl-
2 channel proteins
Facilitated diffusion Na+,Cl-
Describe what happens if there’s excess water near the epithelial cell membrane
Na+ AT out cell by Na+ pump
Low conc inside cell
Na+ FD in cell by channel
Cl- moves down elec gradient (gap between cells)
Na+ charge balanced
Tissue fluid, low water potential
Water -> cell -> osmosis -> tissue fluid
Water -> mucus-> osmosis -> cell
Mucus -> stickier
Describe what happens if there’s too little water near the epithelial cell membrane
// Cl- AT in cell by Cl- pump
High conc inside cell
// Cl- FD out cell by open Cl- channel
// Na+ moves down elec gradient (gap between cells)
Cl- charge balanced
Mucus, low water potential
Water -> cell -> osmosis -> mucus
Water -> tissue fluid-> osmosis -> cell
Mucus -> looser
Describe how the CF protein effects epithelial cell membrane function
CTFR channel doesnt work
Na+ channel open always
Na+ always absorbed from mucus
Draws Cl- and water out mucus
More viscous mucus
Hard for cilia to remove
What is an enzyme
Globular
Biological catalyst
Lower activation energy
Unchanged themselves
Anabolic example
Maltase
Digests maltose -> glucose
Saliva
Catabolic examples
Lipase
Digest fat in gut
Amylase
Digests starch -> sugar in saliva
Trypsin
Digests proteins -> AAs, SI
Diploid cell
46 chromosomes 23 pairs
Made from 2 haploid cells
Haploid cell
23 chromosomes
Gametes (sperm + egg)
Cystic fibrosis symptoms
Severe coughing (remove excess mucus)
Breathlessness (O2/energy shortage)
Infections (bac in mucus)
Respiratory CF effects
- Lung infections, cilia cant move, thick mucus build up, low O2, poor diffusion, anaerobic bac thrive, trapped, infection, cough to clear, damage tissue, inflammation
- reduce gas exchange, mucus blocks bronchioles, fewer alveoli, less SA, more dd, lower rate, in not out, over inflation, elasticity damage
Digestive CF effects
- Pancreatic tube blocked, Enzymes can’t reach SI
- Mucus -> pancreatic cysts! Less enzyme production
- Mucus coats I lining
Less food absorption
Key nutrients lost
Reproductive CF effects
Mucus prevents infection/regulate sperm progress
Teste tubes blocked, sperm can’t reach Lena
Cervical mucus, prevent fertilisation
Name 3 medication CF treatments
Bronchodilators
Antibiotics
DNA enzymes
Bronchodilators
Nebuliser inhaled drug
Opens airways
Relax msucles
CF antibiotics
Lung infections
Kill lung bacteria
DNA enzymes CF
Nebuliser inhaled
Infection, more WBC, more DNA, more stickiness
Enzymes break down DNA
Mucus easier to clear
CF diet treatment
High energy foods
2X protein
Salt supplements
Digestive enzyme supplements CF treatment
Pancreatic duct blocked
SI can breakdown/absorb food
Physiotherapist CF treatment
Rhythmical chest cavity wall tapping
Loosen mucus
Improve air flow
2X a day
Gene therapy CF treatment
Replace mutated gene (normal allele -> GM virus/liposome -> target cells -> tt -> functioning protein)
Inactivate mutated gene
Repair mutated gene
Introduce new gene to fight genetic disorder
CF genetic screening test
Salty skin
High trypsinogen
Before/during pregnancy
Uses of genetic screening
Confirm diagnosis
Identify carriers
Test embryos
Amniocentesis
Invasive
Foetal cells
Cultured before analysis
1% miscarriage
10 weeks
Choronic villus sampling
Invasive
8-12 weeks
Placental tissue
Vaginally
1-2% miscarriage
Earlier, abortion decision easier
Prenatal diagnosis
Non invasive
DNA fragments in mothers plasma
7-9 weeks
Screen few single gene disorders
No miscarriage risk
Preimplantation genetic diagnosis
Cell from embryo 8-16 cells
DNA analysed
Choose implantation
Expensive
In vitro fertilisation
Oocytes removed by syringe
Sperm sample
Solution
Zygotes -> culture solution -> embryos
Genetic test
2/3 vaginally inserted to uterus
Ethical framework
Rights and duties
- baby right to life
- mother right to preserve life
- right to autonomy
Utilitarianism
- maximise good
- deliver suffering baby, use resources
- still bring parents joy
Virtuosity
- love irrelevance
Autonomy
- informed, consensual
Genetic counselling
Explain tests
Discuss courses of action
Probabilities
Screening
Difficult decisions
Practical evidence for semi conservative DNA replication theory
E. coli grown in N15 medium
Centrifuge = low line
N14 medium, isolate 1st generation
Centrifuge = middle line
2 lines (high and low) would be conservative
N14 medium extended
Centrifuge = high line and middle line
1 middle line would be fragmentary
