gen bio 2 exam 2 Flashcards
Channel Proteins
Pore allowing for diffusion with aqueous interior
Has both open and closed states
Still need/follow the concentration gradient
Gating
Is the channel protein open/closed
Selectivity
What is let through the channel protein
Ligand Gated
A ligand is what opens the channel protein
Voltage gated
Opens the channel protein by votage differences, usually -70 mV inside cell, 30 outisde
Mechanically gated
Channel proteins open when they are stretched
Aquaporins
Channel proteins for water
Carrier Proteins
Bind a molecule, and bring it to the other side of a membrane
Random switches between its 3 states
Passive
Need concentration gradient
Transport Maximum
Carrier proteins are not infinite, and can not move infinite molecules
Pump
Active
Integral membrane protein
No concentration gradient is required
Sodium Potassium Pump
3 Sodium out (15 mM inside, 150 mM out)
2 Potassium in (140 mM in, 5 mM out)
1 ATP uses
Exocytosis
Stuff in a vesicle is sent to the cell wall where the membranes connect, and lumen contents deposited into extracellular fluid
Endocytosis
Phagocytosis
Pinocytosis
Receptor mediated endocytosis
Phagocytosis
“Cell Eating”, cell evaginates around an item, and cell membrane extends out towards around it to take it in as a vesicle
Pinocytosis
“Cell Drinking”, exocytosis but just extracellular fluid no item
Receptor mediated endocytosis
LDL connect to LDLRs, and when enough of them are cluster this triggers coating proteins attached to intracellular parts of LDLRs to cause evagination of the cell membrane
Digestion of vesicles
Lysosomes merge with the vesicles, and causes the LDLs to be removed from the LDLRs and then the cholesterol is broken down
Energy
Physics - capacity to do work
Biochem - capacity to cause change
Potential Energy vs Kinetic Energy
middle school science moment
1st + 2nd law of thermodynamics
1: Energy can not be created/destroyed, only change forms
2: Energy becomes more unstable/unusable as it changes forms
Entropy
increases over time, can be thought of as disorder/unusable energy in a system
H = G + TS
Total energy = Usable Energy + (Time*Unusable Energy/Entropy)
delta G
dG = G-products - G-reactants
if dG > 0, energy absorbed
if dG < 0, energy released
Exergonic vs endergonic
Exer = release, ender = absorb
If a cation channel is open, where does Na+ flow?
Generally out to in, but highest concentration to lowest concentration
If a cation channel is open, where does Cl- flow?
it doesn’t, cl- is an anion
What is metabolism?
All chemical reactions in the human body
anabolic metabolism
- Synthetic metabolism
- Small molecules combined to larger ones, energy stored in chemical bonds
- required energy input
catabolic metabolism
- breaks down large molecules to small molecules
- energy in the bonds is released
How does delta G effect the reversibility of reactions?
The higher the delta G the more difficult it is to reverse the reaction
What is the function of enzymes?
Make it easier for reactions to occur, lowers activation energy
Often end with -ase
How do enzymes work?
1) Proximity Reorientation
- brings substrates together in better position o make reaction easier
2) Physical strain
- makes substrate more unstable
3) chemical charge changes
- changing chemical properties of the substrate makes more unstable
how do temp/pH effect enzyme effectiveness?
There is an optimal pH and temperature, and the further you get from each optimum the effectiveness of the enzyme decreases
How does aspirin cyclooxygenase
Aspirin inhibits the enzyme to stop leukotrienes and protoglastins
Irreversible enzyme inhibition
when the inhibitor permanantly binds to an enzyme
Types of reversable inhibitors
A) competitive : inhibitor binds to the active site of the enzyme
B) Non-competitive: the inhibitor binds to a different spot of the enzyme
Types of cofactors
Inorganic: Cu Fe Mg Zn
Organic: porphyry in hemoglobin holding the iron
ATP structure
An adenine (nitrogenous base purine, 2 rings) attatched to a ribose sugar 95c) at carbon 1’, and the phosphates attatch at carbon 5 w/ high energy bonds
What is oxidation?
The loss of electrons
What is reduction?
The gain of electronsT
Two main electron shuttles
NAH+ and FADH+
NAD+ redox reaction
NAD+ (oxidized) -> NADH (reduction)
FADH redox reaction
FADH+ (oxidized) -> FADH2 (reduced)
What is the primary fuel source of the body to make ATP
Glucose is the primary fuel source of ATP production
What is glycolysis?
Breaking down of 1 glucose to 2 pyruvate molecules in the cytosol
Anaerobic respiration
occurs when o2 levels or enzyme levels are low
Either produces lactate in rbc, muscles, or bacteria (3c)
Or yeast/bacteria produces ethanol and c02
Aerobic respiration
occurs when o2 levels and enzyme levels are high
initially starts with breaking down of pyruvate to acetate (2c) and releasing a co2
krebs cycles
krebs cycle
acetate breaks down to 2 co2 and releases one high energy electron to the etc
Electron transport chain
etc leads to oxidative phosphorylization, ADP + P -> ATP, making 26-28 ATP with one glucsose. oxyen
Glycolysis general
- Splitting of sugar in cytosol
- 10 Steps
- 1 Glucose -> 2 pyruvate
Glycolysis Steps
1) Glucose (6c) -> Glucose 6-Phosphate (ATP-ADP)
2) Glucose 6-Phosphate -> Fructose 6-Phosphate
3)Fructose 6-Phosphate -> Fructose 1,6-Phosphate (ATP - ADP)
4) Fructose 1,6-Phospate -> Dihydroxyacetate Phosphate + Glyceraldehyde-3 Phosphate (DHAP racemizes to G3P)
5)…. NAD+ gets reduced (twice) and ADP->ATP (twice)
ends with 2 pyruvate made
….H.O.O
H-C-C-C-O -
….H
Fermentation
Pyruvate turns into
1) Lactate
….H.H.O
H-C-C-C-O-
….H.H
or…
2) Ethanol and CO2
and the NADH formed in glycolysis turned back to NAD+
Pyruvate formula
C3H3O3
Lactate formula
C3H5O3
Aerobic Respiration
1) Pyruvate sent through into the mitochondrial matrix, active transport (NAD+ -> NADH, and CO2 lost)
2) Pyruvate is now acetate, is combined with Acetyl CoA to make Acetyl CoA
3) Acetyl CoA combined with Oxaloacetate (4c) to make Citrate (6c)
Acetate formula
C2H3O2
Citric Acid Cycle
1) Citrate to 5c molecule (Co2 lost, NAD+ -> NADH)
2) 5c molecule to 4c molecule (NAD+ ->NADH, and CO2)
3) GDP -> GTP
4) FAD+ -> FADH
5) H2O lost
6) NAD+ -> NADH, results in Oxaloacetate, reused in aerobic respiration
this all happens twice per glucose molecule, 2 pyruvates
General Results from Citric Acid Cycle
+2 ATP
+2 GTP
+10 NADH
+2 FADH2
Electron Transport Train
NADH gets oxidized, Cytochrome 1 gets reduced and uses some of a high electrons energy to pump 1 hydrogen into the intermembrane space.
Cytochrome (CTC) gives the electron to CTC 2, passes it to CTC 3 and CTC 3 pumps another hydrogen ion into the intermembrane space.
CTC 3 gives the electron to CTC4, pumps another H+ into the intermembrane space, CTC 4 gives 2 electrons to an O to make H2O (metabolic water)
ATP Synthase complex uses the electrochemical gradient to make 26-28 ATP, is about 38% efficient in turning glucose energy to ATP energy
How are other monosaccharides incorporated into the krebs cycle?
converted to glucose/fructose, polysaccharides broken down into monomers
how are triglycerides catalyzed?
Broken down to glycerol and fatty acids, glycerol -> GTP and fatty acids sent to krebs cycle in 2 carbon intervals ( linoleic and linolenic are 2 essential fatty acids)
how are ptorines catalyzed
broken down to amino acids, amine groups are removed and the r-group determines which step of the krebs cycle they are integrated at (we can only synthesize 12/20 amino acids)
Cyanide
Prevents 4th cytochrome from give its electron to oxygen, backs up metabolism and causes cell to starve
Carbon Monoxide
Displaces oxygen in iron of hemoglobin
Also does same thing as cyanide
What is photosynthesis
metabolic process of taking 6co2 and 6h2o + photons -> c6h12o6 and 6o2
two parts, light dependant (making of NADPH and ATP)
and light independant (uses ATP and NADPH to fix carbon)
Absorption of light energy
A photon excites an electron bringing it up one valence shells, where if will de-excite and fall, releasing energy (in this case releasing another photon)
Anatomy of a chloroplast
Outer membrane
intermembrane space
inner membrane
stroma (cytosol)
Grana (stack of thylakoids)
Photosystem 2
Chlorophyll 680 gets an excite electron from a photon, Chl 680 loses an electron to the ETC, and this makes ATP and this electron is given to reduce Chl 700 (water is the oxidized to reduce Chl 680)
Photosystem 1
Chl 700 is excited by a photon, except its excited electron does to reduce NADP+ -> NADPH, Chl 700 is reduced by electron from ETC. NADPH + ATP from PS-2 go to light independent reactions
Where do chemical bond energy originate?
Glucose/food
Where is the carbon after… (carbon book-keeping)
glycolysis
fermentation
aerobic respiration
pyruvate
co2+ ethanol/lactate
co2
Chemiosmotic mechanism n chloroplasts
Protons concentrated in thylakoids, chl680 ECT pumps protons into thylakoid,
Cell cycle is important for…
1) growth in multicellular organisms
2) repair lost/damaged cells
3) reproduction, sexual/asexual
Four events for cell division
1) signal to reproduce, ligand or favorable environment
2) replication of genetic material
3) segregation of genetic material to daughter cells
4) cytokinesis, the division of the cell
How do prokaryotes divide?
binary fission
Chromatin
DNA and associated proteins
Chromatid
two chromatids make up a chromosome
Chromosome
condensed chromatin, histones condense it
Naked DNA
has no proteins
Nucleosome
histones and DNA around it, 4x2
linken DNA
DNA inbetween nucleosomes
Gene
DNA that codes for a protein
Differentiation
what genes a cell expresses
Interphase
G1: Gap 1, cell lives normally
S: synthesis, duplication of DNA
G2: prep to divide, and enlarges, accumulates nutrients
S + G2 centrosome duplicates and migrates to pole
G0
not in the cell cycle
M phase
mitotic phase
Prophase
Prometaphase
metaphase
Anaphase
telophase
Anatomy of chromosome
2 sister chromatids connected by centromere, and has kinetochore proteins
Prophase
Chromatin to chromosome and centrosome migrates
Centrosome
2 centrioles connected forming a right angle, have microtubule fibers connecting to center
Prometaphase
nuclear envelope breaks down, chromosomes move to the mitotic spindles
Metaphase
Chromosomes aligned at the center of the cell, pulled on by mitotic spindles
Telophase
Chromatids pulled apart to opposite poles
Chromosomes to chromatin
Spindle apparatus dismanteld
Cytokinesis
MTOC
Microtubule organizing center (centrosome)
Meiosis general
gonads
2 nuclear divisions
4 n cells
creates genetic diversity
Meiosis 1
Synapse
Cross Over
Independant Assortment
Segregation
Prophase 1
Chromatin -> chromosome
centrosomes -> opposite poles
Chromosomes pair up
nuclear envelope dissapates
chromosomes attatch to spindles
Synapses -> tetrad formation -> crossing over
Metaphase 1
homologous pairs align at equator of the cell
independant assortment
Anaphase 1
homologous pairs pulled away to poles (still 2 chromatids, segregation)
Telophase 1
nuclear envelope rforms
MTOC dissasembles
chromsome -> chromatin
cytokinesis follows
Interkinesis
stage between meiosis 1 +2
Prophase 2
chromatin -> chromosome
MTOC assembly
Nuclear envelope dissipation
chromosomes to MTOC
Metaphase 2
Chromosomes align at equator of cell
Anaphase 2
Homologous pairs puled apart, sister chromatids migrate to edge of cell
Telophase 2
MTOC disassembly
nuclear envelope reforms
chromosome -> chromatin
4 haploid cells (chromatids)
Cystic Fibrosis
A mutation that causes the chloride transporter in simple columnar epilthelium of air passageways to not work, preventing osmosis, low water content in mucus, high mucin protien concentration makign the mucous exxtremely thick
LDL
Brings cholesterol to tissues
HDL
Brings cholesterol to liver, then bile, then feces
Familia Hypercholesteremia
LL severe, causes nonfunctioning LDLR receptors
Ll is mild
ll is normal
Polygenic Inheritence
Inheritance based on two or more traits/loci
plerotrophy
single locus that affects multiple traits
Merton Syndrome
One locus mutations causes:
- Thinness
- Limb elongation
- hyper mobility
- lens discoloration
- increase risk to heart disease
Penetrance
proportion of people with a genotype that express the expected phenotype
example, 5% of people with huntingtons don’t express the diease
Length of the human sex chromosomes
y - 25-40 loci
x - 800 loci
Hemizygous
one pair of chromosomes, each is different
Why are autosomal recessive disorders more common than autosomal dominant?
Dominant less likely to pass on the gene
PKU
phenylketonuria
- can’t metabolize phenylalanine
- build up this AA is toxic to neurons
- not lethal, manageable
Sickle cell genotypes
AA - no SC
Aa SC trait (mild)
aa SC anemia (severe)
Tay Sachs
Loss of an enzyme that metabolizes glycolipids, build up in the brain and is lethal by 5 years old
- not manageable
Non-disjunction
chromosomes fail to separate, and an aneuploidy is caused
3 examples of aneuploidy defects
Trisomy 21 (down syndrome)
trisomy 18 (Edwards syndrome)
trisomy 13 (Patau syndrome)
Klinefelter’s Syndrome
XXY
- Taller, low test
- Some breast tissue
- Low fertility
Small testes
some have no symptoms
Amniocentesis
Take up amitotic fluid through a needle, use it to make a culture of fetal cells and then do a karyotype
Chorionic Villus Sampling
A suction tube shoved up uterus, sucks up placental tissue and grows a culture of fetal cells to then karyotype
