Cell Bio And Genetics Exam 1 Flashcards
How do organisms evolve?
Natural Selection- evolving in response to environment
Adaption by Heritage changes
Survival of fittest, mutations occur then are passed down.
3 parts of cell theory
- Cells are structural unit of life
- All organisms are composed of cells
- All cells arise from pre-existing cells
Endosymbiotic Hypothesis
Origin of eukaryotic cells from prokaryotic cells phagocytosis, once symbiosis become obligatory, transfer of DNA to nucleus of prokaryotic cell.
3 domains of life
- Bacteria
- Archea
- Eukarya
Selective pressures
- Cells must be large enough to accommodate all DNA
- Must be able to get solute across cell in a reasonable amount of time
- Must be able to communicate with the enviornment
SA/V ratio
V= volume of cytoplasm
Want small volume so the nucleus has more control over the cell to respond to the environment
Organic Molecules
Always contain C+H dissolve in water
Inorganic molecules
Ionic bonding, no c, dissolves into ions
Biotic evolution(def and mechanisms)
Def: genetic change in pop that is inherited
Mechanisms: genetic variation and natural selection
Chemical evo(accepted origin)
Accepted origin: formation of complex organic molecules created by smaller inorganic atoms/molecules in the ocean. Depends fundamentally on atomic structure.
6 atoms used in organic molecules and why
CHNOPS (almost always polar covalent) and are highly electronegative
Electronegativity of an atom is defined by:
- Number of protons in atomic nucleus
- Distance b/t protons in nucleus and valence e- (extra shells are harder to control)
- E- repell each other
Cation
Positive ion
Anion
Negative ion
Water special props (why its important)
- Polar
- Excellent solvent
- High specific heat
- Can be s,l, or g within temps suitable for life
- Solid form less dense
- Hydrogen bonds\
These properties make probiotic life possible
Urey and Miller proved…
Organic molecules can originate from non-organic precursors such as air
How old is chemical evo and bio evo?
Chem evo: 4.2 bill yrs ago
Bio evo: 3.8 bill yrs ago
2 larger functions proteins perform. Examples?
Metabolism: enzymes, hormones, gene regulation, transporters
Structure: contractive, antibodies, support
Amphipathic
Having both hydrophobic and hydrophilic ends
Steps of building a protein
DNA (transcription)
mRNA (translation)
Amino acid sequence (folding)
Alpha helix or beta sheets
Glycine
Smallest amino acid r group (just H)
Proline
Covalent bond back from R-group to amine group causing it to be cyclic. Causes kink in beta sheet protein folding is nonpolar
Cystine
Disulfide bonds important to folding through disulfide bonds
Who was the first to identify cells?
Anton van Leeuwehoek Dutch 1600s simple microscopes
Robert Hook British 1600s compound microscope
What did Schleiden study?
plant cells
what did schwann study
animal tissues
anaerobic
Fermentation in cytosol (pyruvate is converted to lactate where most free energy remains and 2ATP are released
thermophiles
able to live in very hot enviornment
how long ago did pigments like chlorophyll form
2.5 bill yrs ago
oxygenic photosynthesis
Energized membrane ADP + P= ATP and a decreased energy membrane
aerobic prokayrotes evolved…
2 bill years ago
eukaryotes evolved…
1.2 bill yrs ago
metazonas(plants and animals) evolved
60 mill yrs ago
Why is Microbial diversity immense?
evolving for 3.8 bill yrs
How was Spontaneous Generation(abiogenesis) refuted
Louis Pasteur’s swan-necked flask experiment elliminating air showing that water won’t form life spontaneously
Whittaker: 5 kingdoms
plants, animals, protists, monera, and fungi
Carl Woese (1972)
16SrRNA as exmaple to popose 3 domains
Endosymbiosis and the Evolution of Eukarya
An alpha mitochondria (proteobacterium) or a cyanobacterium was recognized and engulfed by a primitive anarobic eukaryote, but wasn’t distroyed. Bacterium underwent both physiological and genetic integration, creating obligatory dependency.
Evidence to support Endosymbiosis
- mitochondria and chloroplasts resemble bacteria size and appearance
- like bacteria, mitochondria, and chloroplasts have their own DNA
- the ribosomes of chloroplasts resemble those of bacteria
- 16SrRNA sequences found in mitochondria and chloroplasts support their deriviatio from prokaryotes
Eukaryotic mRNAs are typically composed of…
introns (noncoding) and exons (coding) sequences
Genes are transcribed into… and processed into… in the….
mRNA… mature transcripts… nucleus
mature mRNAs are then …. to the… where they are… into… at the ….
transported… cytoplasm… translated… protiens… ribosomes
4 parts of an amino acid aside from central carbon
amino group, carboxylic acid group, hydrogen atom, and r group
peptide bonds (what are they and how are they formed)
covalent bonds between amino acids, formed by dehydration/condensation reactions formed between a carboxyl group and a amino group
N terminus
the amino terminus at the start of a protien
C terminus
the carboxyl terminus which is the growing end of the protien, where more aminos are added
4 groups of amino acids
Polar charged residues, polar uncharged residues, non polar amino acids, special amino acids
polar charged residues (examples)
such as aspartic acid and glutamic
polar uncharged residues
are not charged despite the fact there is an uneven distribution of electrons
non polar amino acids
often associated with lots of methyl groups, example, alanine, valie, leucince, isoleucine, phenylalanine, tryptohtan
special amino acids
glycind- smallest cysteine- forms disulfide bonds which are important to folding proline- forms covalent bond with amine group and r group
How do amino acids make a difference in resulting protien?
- polar vs nonpolar
- hydropillic vs hydrophobic
- charged vs uncharged
- small vs large (based on r groups)
Primary Structure
sequence of amino acids within protien that determines protien’s 3d structure peptide bonds
Secondary structure
refers to conformation of small portions of polypeptide chai alpha helix and beta pleated sheet. hbonds
Tertiary structure
3d conformation of the protien, h-bonds, other noncovalent interactions (vander walls force, disulfide bonds)
Quarternary Struct
Some protiens are not comprised of a single polypeptide chain, but rather multiple chains
Protiens are dynamic
Can change confirmation, especially when something binds to it. Can make certain protiens active or inactive
Hydrophilc
Polar attracts water
Hydrophobic
Non-polar, repells water
Enzymatics
- Almost all enzymes are protiens
- ES complex is non covalently bound
- Chemical reactions can happen w/o action of enzymes but occur slowly
- Enzymes speed up rate at which ractions occur
- Enzymatic reactions are bidirectional, and the concentration of substrate and product determines direction that rxn will occur
- has a reaction rate r
exergonic and endogonic rxns are ….
coupled energy created from exergonic rxns are used to preform endogonic
2 laws of thermodynamics
- energy can not be created or destroyed only transferred or transformed
- events in universe occur “down hill” from higher to lower energy state
Free Energy G… delta G
is the energy that is avaliable to do work… is the free energy released when reactants are converted into products understandard conditions
Steady State metabolism
reactants and products are constant because:
1. the products of one reaction become substrates for the next
2. new substrate is brought ffrom outside of the cell, and terminal products are removed
How do enzymes lower activation energy
Enzymes bind more tightly to the transition state than to reactantss. this binding stablizes teh activated complex and decreases the energy
lock and key model
just as locks are unique to their keys, the enzyme has a shape that is complementary to that of its specific substrate
induced fit model
not all enzymes will fit the substrate like a lock and key; rather, the interaction of E and S enduces the fit. Namely the substrate induces a confirmational change in the enzyme such that E/S is induced
active site
where the substrate binds to te enzyme
membrane functs
- barrier- seperates interior of cell from enviornment
- transport- regulates entry and exit of solutes
- intercellular interaction- cell adhesion
- response to external stimuli- cell signaling
- scaffold for reactions- it coordinates metabolic pathways
membrane made of
lipids- phospholipids, glycolipids, sphingolipids, sterols
protiens-glycoprotiens, lipoporitens, integral, periphrial
carbs- covalently linked glycolipids
membrane structure
phospholipid bilayer- hydrophobic tails and hydrophilic heads
fluid mosaic model
the cell membrane as a tapstry of phospholipids, cholesterols, and protiens that are constntly moving
2 experiments that support fluid mosaic model
- cell fusion expeiments
- FRAP
FRAP is most effective when most of the lipids are…
unsaturated
How does cholesterol affect phase transition temperature of a membrane?
A pure phospholipid bilayer changes from a gel to liquid rather quickly. This is because it impacts the ability for hydrophilic tails to densely packed.
sphingolipids
consists of a sphingosine consists of a log FA chain attached to a glycerol moiety, not via the acyl ester linkage.
alloysteric inhibition
binds to protien causing confirmational changes and effects the ability of enzyme to attach to substrate
competetive inhibition
inhibitor attaches to active site of enzyme stopping it from creating product
2ndary active transport
transport across concentration gradient use ATP generated by passive transport from another molecule moving with concentration gradient
cotransporter
moving two solutes at a time
symport
cotransport of solutes moving in the same direction
antiport
cotransport moving solute in oppisite directions
outer membrane of mitochondria
50% lipid
outer membrane of mitochondria
3:1 protein:lipid (cristea) where the e- chain takes place is highly impermeable has lots of special transporters for molecules and ions. Some specific to Ca2+ transport since another mitochondrial role is to regulate cytosolic calcium concentrations.
Substrate level phosphorlation
Where an enzyme creates ATP through attaching a P to an ADP, does not yield a lot of ATP
NAD+ is a….carrier
NADH is considered…
Hydrogen
Reducing power
Glycolysis
Glucose secondary active symbiotic transport
C6H12O6—- 2 pyruvate
2ADP + 2P—— 2 ATP (substrate lvl phosphorylation)
2NAD+ +2H—— 2NADH(reducing power) +H+ (high energy e-)
Phophofructokinase
An allosteric regulator of glycolysis takes off phosphate group from ATP
TCA cycle
Happens in mitochondrial matrix
2 pyruvate—- 6CO2 completely oxidized
3NAD+ +2FAD—- 8 NADH +2FADH2
2GDP + P—— 2 GTP (substrate level phosphorylation)
E- transport chain
Occurs in Cristea (outer membrane)
NADH +H—- NAD+
H is split into e- and protons
Creates water and H20
What happens to protons in the e- transport chain
Pumped across then gets brought back across membrane through ATP synthase and creates ATP using energy from protons crossing the gradient
ATP synthase
An enzyme attached to a pump using the energy created from the dissipation of proton motive force to create atp from adp
PMF
Proton motive force
Mitochondrial Matrix
Many enzymes and ribosomes plus double stranded DNA(its own genome!) inner mitochondria
NADPH vs NADH
NADPH moves e- around w anabolic reactions
NADH moves e- around w catabolic reactions
Aerobic respiration
In mitochondria pyruvate is completely oxidized to CO2 and a lot of high energy electrons ultimately makes 32-36ATP
Chemiosmosis
The processes by which energy stored in e- is converted into chemical energy in the form of ATP
NADH dehydrogenase
Accepts H atoms and donates them to next player in ETS (NAD-NADH)
Flavoproteins
Derived from riboflavin. Can accept h atoms and donate e-. Here where the H is split into protons and electron considuents (FAD-FADH2; FMN-FMNH2)
Cytochromes
Proteins with a heme prosthetic group: can accept and donate only e-
Ubiquinone(Coenzyme Q)
Non-proteinaceous and lipid soluble. Can accept H atoms and donate e- (like flavoproteins)
Iron-sulfur proteins
Iron containing proteins that can accept or donate e-, but the iron atoms are not associated with a heme group; rather, linked to inorganic sulfur atoms associated with cysteine residues.
What function does O2 serve in the electron transport chain
O2 is very electronegative and pulls e- through the chain, acts as final e- acceptor
ATP/ADP translocase
A transmembrane enzyme that moves ATP out of cell after creation
NADH creates … ATP
3
FADH2 creates…ATP
2
Inter membrane space
Between inner and outer membranes swells during active transport
basic amino acids are
positively charged
acidic amino acids are
negatively charged
cofactors
bind to active site are non proteins and are essential for amino acid activity
zwitter ion
ionized version of an amino acid ionization varies with ph
pyruvate dehydrogenase
pyruvate into acetyl CoA and Co2 before entering TCA cycle
