BIO/BIOCHEM Flashcards
What is the role of signal sequence ?
Signal sequence : a portion of mRNA that is located in the 5′ region and will signal to the ribosome that translation needs to be continued in the rough endoplasmic reticulum.
What is the nuclear localization signal ?
Nuclear localization signal : is a sequence that tags the protein for it to be transported into the nucleus
What does a mature RNA sequence for a protein located on cell membrane contain ?
mature RNA sequence for a protein that is secreted or that will locate to the cell membrane will contain the SIGNAL SEQUNCCE.
What is the role of calcium during muscle contraction process?
Ca2+ binds to troponin and allows tropomyosin to move, freeing the site of interaction between actin and myosin.
How many fused rings are in steroids ?
4 fused rings (contain 6-6-6-5 fused ring assembly)
What can fix an epileptic issue due to massive firing of neurons in a small area ?
An INCREASE in neuron firing threshold would make it more challenging for a neuron to fire an action potential. This will reduce the frequency of downstream neuron depolarizations, resulting in relief of the symptoms.
Which region of the kidney is glomerular filtrate most concetrated ?
Medullary portion of collecting duct
(last part of tubule where reabsorption of water and salts occur)
What occurs in proximal convoluted tubule ?
portion of tubule where glomerular filtrate First passes through
What is role of collecting duct ?
collecting duct: concentrates filtrate
assuming no denaturation of proteins, what is expected to increase with temperature ?
PROTEIN ACTIVITY (expected to increase with temperature)
How are action potentials stimulated ?
by release of a neurotransmitter that binds to ligand gated channels,
What is the role of Na+/K+ ATPASE during a neuronal action potential ?
aids in The RESTORATION and maintenance of the RESTING POTENTIAL.
This is achieved by moving three Na+ out of the cell for every two K+ ions that are brought into the cell.
What is the function of transcription factors ?
regulate the expression of other genes ( by binding to the promoter or the enhancer of the gene located on the DNA).
How do hydrophobic molecules pass through membrane ?
SIMPLE DIFFUSION
What must occur for regulation of the expression of genes to be possible ?
The downstream target genes must contain DNA REGIONS in their promoter or enhancer, that can interact with transcription factors
What is produced after ATP hydrolysis ?
ADP + Pi (inorganic phosphate)
What are lipid rafts?
lipid rafts: cholesterol rich domains within the membrane
What is the role of microtubules ?
Microtubules: bind to chromosomes at the level of the kinetochore and regulate their migration toward the opposite poles of the cell during anaphase.
What regulates to formation of filtrate in Urinary system ?
The DIFFERENCES IN PRESSURE regulate filtrate formation
what are the main pressures that work in urinary system and how do they work ?
There are three pressures that work together to regulate filtration in the glomerulus:
-glomerular capillary pressure
-capsular hydrostatic pressure
- blood colloid osmotic pressure.
The glomerular capillary pressure will force filtrate from a capillary into Bowman’s capsule; the other two forces promote movement of the filtrate in the opposite direction.
How do enzymes alter the rate of chemical reactions ?
Enzymes :
can alter pH of environment
can co-localize substrates to modify rate of reaction
-alter substrate shape
What is a brief summary of translation ?
Proteins are generated during translation.
In this process, mRNA triplets are read by ribosomes, and tRNA molecules provide the amino acids. Each amino acid is matched to a tRNA molecule carrying a specific anti-codon. A specific amino acid will be added only if it is recognized by its specific codon.
What happens to cells in interphase ?
cells in interphase are NOT actively DIVIDING
What do mature erythrocytes NOT contain ?
Mature erythrocytes do NOT contain DNA since they are enucleated (no nucleus)