Chapter 2: Protein Function Flashcards
1
Q
Ribozymes
A
- Catalytic potential of RNA
2
Q
Enzymes
A
- Accelerate the rate at which cellular reactions proceed
- Lower activation energy
- Increase the rate of metabolic reactions by over 10^17 times
- Accelerate the speed at which equilibrium is reached by increasing the rate of forward and reverse reactions to the same extent
- Minimize production of unwanted side products
3
Q
Proteases
A
- Classified according to the specific amino acid involved in catalysis at the enzyme active site
- Serine, aspartate, and cysteine identified
4
Q
Zymogenic proenzymes
A
- Inactive
- Synthesized by serine proteases
- Require limited prtoeolysis for activation
5
Q
Serine proteases
A
- Important in various processes such as the blood coagulation cascade resulting in clot formation and proteolytic digestion
- Some have preference for particular peptide bonds
6
Q
Myoglobin
A
- Serves as a high affinity oxygen storage protein in muscle
- Lacks a quaternary structure
- Consists of a single polypeptide chain
7
Q
Hemoglobin
A
- Composed of 4 globin chains, 2 alphas and 2 betas
- Tetramer with quaternary structure
8
Q
Sickle cell anemia
A
- Genetic disorder of the hemoglobin structure
- Amino acid primary structure is altered
9
Q
Thalassemias
A
- Production of the globin chains is reduced or eliminated
- Alpha chains under produced (alpha ***)
- Beta globin chains affected (beta ***)
10
Q
Iron chelation therapy
A
- Helps manage various forms of thalassemias
- Iron transported in circulation
- Attaches to hepatic glycoprotein (transferrin)
- Transferrin binds to dimeric cell surface receptors, facilitating phosphorylation and internalization
- Iron is released within the cell and transferrin is recycled
11
Q
Transferrin
A
- Hepatic glycoprotei
- Possesses 2 non-cooperative iron binding sites (Fe3+)
- Binds to dimeric cell surface receptors, facilitating phosphorylation and internalization (in iron chelation therapy)
12
Q
Ferritin
A
- Can bind to excess iron to be stored in the liver
13
Q
Saturation kinetics
A
- Movement of molecules across a membrane to increase content on other side
14
Q
Symport
A
- Two molecules move across membrane simultaneously in one direction
15
Q
Antiport
A
- Two molecules move across membrane in opposite directions
16
Q
Uniport
A
- A single molecule moves in one direction across a membrane
17
Q
Collagens
A
- Strengthens skin and bone
- Fibrous proteins
- Unique structure consisting of 2 helical alpha chains
- Can be 1000 amino residues in length
- Chains wrapped around each other and stabilized by hydrogen bonds
18
Q
Alpha-keratin
A
- Fibrous protein with simple alpha helical structure
- Rich in hydrophobic amino acids (phenylalanine, isoleucine, and valine)
19
Q
Protofilaments
A
- Two alpha-keratin chains combine to form a coil that is associated with other coils
- Increase the tensile strength of fibrous structures
20
Q
Antibodies
A
- Specialized group of proteins that defend the body from attack by harmful antigens
- Can be proteins, nucleic acids, bacteria, or viruses
- Similar Y-shaped structures among them
- Up to 1 x 10^8 produced in human body
21
Q
Antibody structure
A
- Composed of 2 identical heavy chains and 2 light chains
- Chains are connected by non-covalent and disulfide bonds
22
Q
Receptor proteins
A
- Bind ligands and mediate cellular responses to external stimuli
23
Q
3 domains of cell surface receptors
A
- Extracellular ligand-binding
- Transmembrane hydrophobic
- Intracellular
24
Q
Beta 2 - adrenergic receptor
A
- Serpentine 7-pass receptor protein
- Consists of polypeptide chain that spans the cell membrane 7 times
- Signal transduction is mediated through action of other membrane proteins (G-proteins and adenylate cyclase)
25
Intracellular receptors
- Receptors proteins for hydrophobic steroid hormones and thyroid hormones
26
Growth factors
- Proteinaceous in nature
- Mediate cell growth and development
- Derived from large precursor molecules
- Stimulate cell growth by effecting receptor dimeriazation and autophosphorylation
27
Transcription factors
- Bind non-covalently to selected regions of a cell's DNA
| - Controls selective gene expression and cell differentiation
28
Primary structure review
- This protein state is closely linked with the protein's function
29
Classification review
- Proteins can be organized on the basis of their function
30
Protein functions review
- Proteins possess catalytic potential and may also serve as transport and storage vesicles
- Crucial for movement, mechanical support, and defense of our bodies
- Integral part of signal transduction
31
Growth factors review
- Play a role in cell division
32
Transcription factors review
- Crucial to gene expression
