Exam 1 Flashcards
Polar molecules are…
hydrophilic
The four weak bonds are:
Ionic, Hydrogen, Hydrophobic, Van der Waals
What is PAGE-SDS?
Electrophoresis: Used to isolate fragments that contain a gene of interest
What is electronegativity?
The attraction of electrons to a certain molecule
What is a peptide bond?
A covalent bond between an amino group (N terminus) of one AA and a carboxyl group (C terminus) of another AA
How do peptide bonds occur?
Dehydration synthesis (removal of water)
What is the primary structure?
Sequence of amino acids to form polypeptide chain
What is the secondary structure?
An alpha helix OR beta sheet (ONLY BACKBONE (NO R GROUP))
What is the tertiary structure?
More compact, R groups interacting, all weak bonds AND disulfide bonds. Folding of domains based on hydrophilic/phobic interactions.
What is the quaternary structure?
Polypeptides all bonded, in one group
What is a domain?
any segment of a polypeptide chain that can fold into a compact, stable structure
What purposes do proteins serve?
Enzymes, structural, transport, storage etc…
What is the effect of temperature on proteins?
More heat -> increased kinetic energy (proteins move around more), too much = protein denatures
What is the effect of pH on proteins?
Change of concentration, changes how the amino acids bind to one another, changes charge of protein/function
What is ligand binding?
Binds two receptor proteins and can change the shape/conformation of the protein.
What is the difference of anabolism vs catabolism?
Catabolism breaks down large molecules and RELEASES energy, while anabolism builds large molecules and REQUIRES energy
What is metabolism?
All chemical reactions that occur in a cell to transform matter and energy
What is the formula for change in G?
ΔG = ΔH - TΔS
What is Gibbs Free Energy?
The energy available to produce useful work
What is ΔH?
It is enthalpy, or the energy contained in chemical bonds
What is ΔS
It is enthropy, or the amount of disorder (heat released)
If ΔG is less than 0…
The reaction will occur spontaneously (energetically favorable)
If ΔG is more than 0…
The reaction will not occur spontaneously (not energetically favorable)
How do enzymes work?
Enzymes attract substrates to the active site, then catalyzes the chemical reaction, and breaks down the substrate so it can form new bonds!!!
What is an induced fit model?
Also known as the “Enzyme Substrate Complex”, a combined structure of the enzyme and its substrate bound to the active site
What are cofactors?
Small and inorganic molecules which help enzyme function
What are coenzymes?
Organic molecules that bind to the active site to help finalize the shape of the site
What are inhibitors?
Molecules that reduce the activity of an enzyme (they INHIBIT the enzyme)
What are the two types of inhibitors?
Competitive inhibitor (interferes directly with the active site)
Allosteric inhibitor (interferes indirectly to active site, changes shape of enzyme at allosteric site (other part))
What are coupled reactions?
Energy transferred from one reaction to another (EXAMPLE ATP COUPLING)
What are sugars?
They are a quick energy source
Name some important disaccharides.
Sucrose, Maltose, Lactose
Name some important polysaccharides.
Starch, Glycogen, Cellulose, Chitin, Peptidoglycen
What are the roles of lipids?
Long term energy storage (triglycerols), structural (phospholipids), hormones (steroids)
What are the four family groups of lipids?
Triglycerides, phospholipids, steroids, and waxes
What is a triglyceride?
Formed from one glycerol molecule, bond to 3 fatty acid molecules (lots of bonds, better for energy storage)
What are fatty acids?
A hydrocarbon chain ending in a carboxyl group (can be saturated or unsaturated)
What are phospholipids?
A component of the cell membrane that contains hydrophobic and hydrophilic ends
The head is hydro____ and the tail is hydro_____
philic, phobic
What are steroids?
Composed of carbon-based rings, includes cholesterol and sex hormones
What are the roles of the cell membrane?
Manage what enters and exits the cell through the membrane.
What are the factors of fluidity in the cell membrane?
Temperature: Higher temp = more fluidity
Phospholipid composition
Nature of hydrocarbon tails
Amount of cholestrol
The more unsaturated, the more…
viscous/liquid
What is a liposome?
The double layer that is formed by the phospholipids
What is a micelle?
The single layer that is formed by phospholipids and counterions
The polar heads face the ______ and the non polar tails face _____.
Aqueous environment, inside
What is fast lateral movement?
The membrane acts as a fluid, with two layers sliding across each other
Difference between saturated and unsaturated fatty acids
Saturated fatty acids: No double bond on the tail, more rigid
Unsaturated fatty acids: Double bond on the tail, forms kinks, more fluid
What are the types of proteins on the membrane?
Transporters, anchors, receptors, enzymes
What can pass through the bi-layer quickly?
Small, hydrophobic molecules like oxygen and carbon dioxide
What are integral membrane proteins and how do you remove them?
Transmembrane, membrane-associated, and lipid linked proteins that are attached to the lipid bi-layer (removed with detergent)
What are glycoproteins?
Phospholipids with a sugar on the surface
What do phospholipids do?
Helps with cell membrane structure and acts as a receptor
What is diffusion?
Molecules moving from high to low concentration (does not require energy)
What are the active and passive transport methods through the membrane?
Passive transport requires no energy, active transport requires ATP or potential energy
What is the difference between a symporter and an antiporter?
Symporter: ion helps molecule over using its energy in the same direction
Antiporter: ion helps molecule over in opposite direction
How do cotransporters work?
The carrying of two or more molecules, with one ion providing energy down its concentration gradient while the other molecule is carried against its gradient
What do genes need to be able to do?
Encode information about traits
Replicate accurately to be passed to the next generation
Change (mutate): variability to fuel evolution
What did Griffith do?
He experimented on neumococcus (Streptococcus pneumoniae)
What did Avery, McLeod, and McCarty do?
They developed
transformation of
pneumococcus type
R using crude
extracts of type S
in vitro
What did Hershey and Chase do?
They discovered the independent functions of viral protein and nucleic acid in growth of bacteriophage
What did Hershey and Chase do?
They discovered the independent functions of viral protein and nucleic acid in growth of bacteriophage
What are the building blocks of DNA?
Nucleic acids
What are the three parts of a nucleic acid?
The base, phosphate, and sugar
What are the 5 different bases?
Adenine, Guanine, Cytosine, and Thymine (Uracil for RNA)
What are the 3 different phosphates?
NMP, NDP, NTP
What are the 2 types of sugars for nucleic acids?
ribose (RNA) and deoxyribose (DNA)
What are phosphodiester bonds?
They form through a condensation reaction (dehydration synthesis), they link the sugars of a nucleotide
How do you identify the 5’ and 3’ end?
The 5’ end is the phosphate (LOOK FOR P)
The 3’ end is the sugar (NOT BASE ACGT)
What is the model of a DNA double helix?
The two strands are antiparallel, with a 5’ prime end of one strand crossing a 3’ end of another strand
How is the sequence of DNA written?
Always from 5’ to 3’
What is the difference between chromosomes and chromatin?
Chromatins are a complex of DNA that is formed by histone proteins, while chromosomes are just genetic material
What are nucleosomes?
Basic structural packaging of DNA in chromatin and a section of protein wrapped around DNA
What is the change in electronegativity for ionic, non polar and polar covalent bonds?
Δx < .5, non polar covalent, .5 < Δx < 2 polar covalent, 2 < Δx, ionic
What are hydrogen bonds?
Between molecules, when the hydrogen of one molecule is attracted to a very electronegative atom of another molecule (O or N)
What are hydrophobic/philic bonds?
does not dissolve in water vs hydrophilic (does)
What are ionic bonds?
Between metal and non-metal, electrons are GIVEN rather than shared (creates ion because mixed electrons)
What are van der Waals interactions?
Slight positive and negative attraction between unevenly distributed electrons in molecules
What is hydrolysis?
Breaking of bonds with water
What is condensation?
The removal of water
Why do all cells have similar compositions?
Cells have similar comp/mechs because they need similar things to survive (energy, water, etc)
Differences between eukaryotic and prokaryotic cells?
Similarities between eukaryotic and prokaryotic cells?
Differences between plant and animal cells?
Similarities between plant and animal cells?
What makes a protein polar?
Has hydroxide(s) (OH), does not have singular H, has N (EXCEPT TRYTOPHAN)
Which nucleic acid bases are purines vs pyrimidines?
The purines are Adenine and Guanine, and the pyrimidines are Cytosine and Thymine, in RNA its Cytosine and Uracil
What is osmosis?
The movement of water into the plasma membrane
With an enthalpy graph, when an enzyme is added, what happens to the curve?
The curve flattens due to less activation energy required
What is endothermic vs exothermic?
Exothermic releases energy while endothermic keeps energy or obtains
