Final Exam Flashcards
What is the structure of the cell membrane? (3)
-Lipids
-Proteins
-Carbohydrates
What is the function of the cell membrane? (3)
-Transport
-Diffusion
-Osmosis
What is the structure of an enzyme? (2)
-Proteins
-Nucleic acids (ribozyme)
What is the function of enzymes? (General)
Catalyzes chemical reactions
What do binding and catalytic sites do?
(Enzymes)
Binding sites: bind and orient substrate(s)
Catalytic sites: reduce chemical activation energy
The type of metabolism involved in the formation of polymers by using monomers is called […]
Anabolism
The type of metabolism involved in the degradation of polymers is called […]
Catabolism
Does hydrolysis or Dehydration produce a net quantity of energy (ATP)?
Hydrolysis: produces energy
Dehydration: requires energy
What are the polar functional groups?
Hydroxyl and carbonyl
What are the non-polar functional groups?
Methyl
What are the slightly polar functional groups?
Sulfhydryl
What are the acidic and basic functional group?
Acidic: carboxyl and phospate
Basic: amino
Synthesis of disaccharide by the […] between 2 […] groups, which makes it possible to make a covalent bond called a […] bond.
Dehydration
Hydroxyl
Glycosidic
What are amino acids composed of?
-amino group
-carboxyl group
-single hydrogen
-central alpha carbon with a side chain (R)
What is the backbone of amino acids?
N-C-C
(It is always the same)
What is special about methionine?
It is always the first amino acid of a polypeptide in eukaryote and archaea
What is special about proline?
It causes kinks in polypeptides
What is special about cysteine?
It contains a side chain with a sulfhydryl functional group, which links chains together to make a disulfide bridge
What are monomers and polymers of amino acids called?
Monomer: amino acids
Polymers: polypeptides (composed of monomers of unbranched amino)
A protein is made up of….
One or more polypeptides and can only be called a protein if the polypeptide(s) have a function
Amino acids are joined by […] synthesis and […] bonds are formed between the […] and […] ends of the two adjacent amino acids.
Dehydration
Peptide
Amino
Carboxyl
What bonds are found in the primary and secondary structure of amino acids?
Primary: peptide bonds between sequence of amino acids
Secondary: hydrogen bonds between amino acids of the backbone (the H of the amine and the O of the carbonyl group in the backbone)
One polypeptide with a […] structure can form a functioning protein
Tertiary
What are motifs (proteins) and name a few.
-Similar structures between otherwise dissimilar proteins
Ex:
helix-turn-helix
Beta barrel motif
Beta-alpha-Beta motif
What are domains (proteins)?
-Functional units within a larger structure
(They can be thought of as a substructure within the tertiary structure of a protein)
(Ex: transcription factors)
What are the 6 protein functions?
1) Enzyme catalysis
2) Defense
3) Transport
4) Support
5)Motion
6) Regulation
What are environmental factors that can affect/change the structure and function of proteins? (4)
-Temperature
-pH
-Organic solvents
-Detergent
(Temperature and ph most important)
What are the 3 family of lipids?
1) Triglycerides
2) Phospholipids
3) Steroids
What are the characteristics of saturated and unsaturated triglycerides?
Saturated:
-No double bonds between carbon
-Higher melting point, animal origin
Unsaturated:
-One or more double bonds
-Low melting point, plant origin
What are characteristics of cis and trans fatty acids? (Triglycerides)
Cis fatty acids: most naturally occurring unsaturated fatty acids have double bonds with a cis configuration
Trans fatty acid: fats that are partially hydrogenated (not natural)
-Linked to elevated levels of LDL (bad cholesterol) and low levels of HDL (good cholesterol). Associated with an increased risk for coronary heart disease
What are the 2 functions of steroids?
-Chemical signalling (hormones like testosterone)
-Have an impact on fluidity of plasma membrane (cholesterol)
What are the molecular constituents of the cell membrane? (3)
1) Phospholipid bilayer
2) Protein (transmembrane protein and interior protein network)
3) Surface markers (mainly carbohydrates)
What is the main difference between integral membrane proteins and peripheral membrane proteins?
Integral membrane proteins: inserted into the phospholipid bilayer.
Peripheral membrane proteins: Attached to the surface of the phospholipid bilayer or to an integral protein
What are transmembrane proteins?
An integral protein that crosses the bilayer completely
What are channel and carrier proteins?
Both are transporter proteins
Channel: have a hydrophilic interior that provides an aqueous channel through which polar molecules can pass when the channel is open
Carrier: bind specifically to the molecule they assist to carry through the membrane (ions, sugars, amino acids, etc…)
What are glycolipids and glyoproteins?
Glycolipids: carbohydrate + lipid
Glycoprotein: carbohydrate + protein
What does cell-to-cell adhesion do?
Bind cells together
What is attachment (for proteins)?
What is the functions of spectrins and clathrins?
(Interior protein network)
Spectrins: determine the shape of the cell
Clathrins: anchor certain proteins to specific sites (especially on the exterior plasma membrane in receptor-mediated endocytosis)
What are the functions of glycoproteins and glycolipids?
Glycoproteins: ‘’self’’ recognition
Glycolipids: tissue recognition
What are the two types of membrane transport?
Passive transport: no energy required,
-molecules move in response to a concentration gradient
(simple diffusion, facilitated diffusion, osmosis)
Active transport: requires energy,
-can move substances from low to high concentrations
Why does simple diffusion work for non-polar molecules but not polar molecules?
The hydrophobic interior of a biological membrane repels polar molecules but not non-polar molecules.
Therefore, non-polar molecules such as steroids will move until the concentration on both sides is equal (but this won’t work well for large or medium sized polar molecules)
What are 3 characteristics to facilitated diffusion?
1) Specific transport (only transports certain molecules or ions)
2) Passive transport (move by diffusion from region of higher to lower concentration)
3) Saturation (transport proteins can get saturated)
What are the 2 types of facilitated diffusion?
1) Channel proteins: hydrophilic interior that provides an aqueous channel through which polar molecules can pass when the channel is open)
2) Carrier proteins: bind specifically to the molecule they assist to carry through the membrane (ions, sugars, amino acids, etc.)
What is the difference between the relationship of concentration and rate of transport for simple diffusion and carriers?
Simple diffusion: linear increase in rate of transport
Carriers: concentration increase means more of the carriers are bound to the transported molecules (Therefore, the rate will be constant at high enough concentrations (saturated)).
What is osmosis?
The net diffusion of water across a membrane towards a higher solute concentration
In biological membranes, water moves through […].
Aquaporin channels
What are hypotonic, isotonic and hypertonic solutions?
(Osmosis)
Hypotonic: the solution has a lower solute concentration than the cell
Isotonic: the solution has the same solute concentration than the cell
Hypertonic: the solution has a higher solute concentration than the cell
What is osmoregulation?
How some organisms maintain osmotic balance
What is turgor pressure?
Plants use turgor pressure to push the cell membrane against the cell wall and keep the cell rigid, thus blocking entry of too much water and giving the plant their rigidity
What is isosmotic regulation?
Some organisms that live in the ocean adjust their internal concentration of solutes to match that of the surrounding seawater. Because they are isosmotic with respect to their environment, no net flow of water occurs into or out of these cells
Active transport requires the use of […] proteins
Carrier
What are the 3 types of active transport proteins?
Uniport: transports one substance in one direction
Symport: transports two different substances in the same direction
Antiport: transports two different substances in opposite directions
What are the 2 types of active transport?
1) Primary active transport: energy (ATP) is used to transport a chemical
2) Secondary active transport: passive movement of one solute with its concentration gradient induces the movement of another solute against its concentration gradient
What are the 2 types of bulk transport?
1) Endocytosis: movement of bulk substances into the cell
2) Exocytosis: movement of bulk substances out of the cell
What are the 3 types of endocytosis?
1) Phagocytosis: eat
2) Pinocytosis: drink
3) Receptor-mediated endocytosis: molecules first bind to specific receptors in the plasma membrane — they have a conformation that fits snugly into the receptor. It acts like a molecular mousetrap, closing over to form an internal vesicle
When is exocytosis used for plants and animals?
Plants: used to export cell wall material
Animals: secrete hormones, neurotransmitters, digestive enzymes, and expel waste
