Bio/Biochem Flashcards
during starvation, the average human being can generate glucose from:
1) glycogen
2) the glycerol portion of triacylglycerol
3) amino acids
where is glucose stored as glycogen in the body?
the liver and muscle tissues
how can glucose be generated from triacylglycerol?
the glycerol portion can be turned into glucose via gluconeogenesis
how can amino acids be used to generate glucose?
AA can be used as substrates for gluconeogenesis
does glycogen or triacylglycerol have more energy?
triacylglycerol
why acetyl-CoA converted to ketone bodies after a few weeks of starvation?
gluconeogenesis depletes the supply of oxaloacetate which is essential for the entry of acetyl-CoA into the Krebs Cycle
what’s generated when you break down fatty acids?
acetly CoA
what happens after you eat a meal?
insulin secretion, glycogen systhesis and glycolysis
what doesn’t happen is glucagon secretion, gluconeogenesis, hydrolysis of triacylglycerol because those raise blood glucose levels
what does gluconeogenesis do?
it’s kind of the reverse of glycolysis
it raises blood glucose levels
what does insulin inhibit?
glucagon secretion
insulin decreases blood glucose levels
glucagon raises blood glucose levels so insulin would inhibit glucagon secretion
what term defines the tendency to have more sever symptoms and earlier onset with greater numbers of a CAG repeat?
increased expressivity
also knowns as anticipation
where are the dorsal root ganglia located?
spinal cord
what are Meissner’s corpuscle?
processing units in the skin
a sensory nerve ending that is sensitive to mechanical stimuli, found in the dermis in various parts of the body.
if RBC were grown on a medium that blocks the ETC, what would happen?
nothing, RBC don’t have organelles
so they don’t have mitochondria to even need the ETC
they produce ATP anerobically
ATP production would not change
what is the vitreous humor?
the transparent jellylike tissue filling the eyeball behind the lens
what would increased levels of H+ do to the anion gap?
it would increase it
you would need more base to make the solution a buffer
what does hypoventilation result in??
decreased oxygen, increased CO2 levels
H2O + CO2
what does hyperventilation result in?
increased oxygen, decreased CO2 levels
H2O + CO2 –> HCO3- + H+
the equilibrium has shifted right
metabolic acidosis
what happens during isoelectric focusing?
amino acids migrate towards a pH near their pI
ex. aspartate has a pI of 3; if you’re at a pH of 4 then it will migrate towards the anode which is at a lower pH
ex. phenylalanine has a pI of 6; at a pH of 4 it would migrate towards the cathode which is at a higher pH
what’s the pH of the anode?
acidic
low pH
things are getting oxidized, losing H+ so it’s acidic
what is the pH of the cathode?
basic
high pH
things are getting reduced, not a lot of H+ around
what is a frameshift mutation?
either an insertion or deletion
a genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three
what is a missense mutation?
a point mutation in which a single nucleotide change results in a codon that codes for a different amino acid
what’s a nonsense mutation?
a mutation in which a sense codon that corresponds to one of the twenty amino acids specified by the genetic code is changed to a chain-terminating codon
what are stop codons?
During protein formation, DNA (or RNA) nucleotide sequences are read three nucleotides at a time in units called codons, and each codon corresponds to a specific amino acid or stop signal (stop codon)
Stop codons are also called nonsense codons because they do not code for an amino acid and instead signal the end of protein synthesis
what is a silent mutation?
A form of point mutation resulting in a codon that codes for the same or a different amino acid but without any functional change in the protein product
what does the lysosome do?
an organelle that contains many enzymes that break down proteins
also key in organelle recycling
what does the peroxisome do?
the breakdown of very long chain fatty acids through beta-oxidation
then they’re shuttled to mitochondria where they are eventually broken down to carbon dioxide and water
perioxisome replicates by division and does not contain its own genome
what does the smooth endoplasmic reticulum do?
the ER is in the cytoplasm
SER helps with synthesis of phospholipids and cholesterol
in the liver, the SER helps with the breakdown of carcinogens
in the adrenal gland and gonads, cholesterol is modified to a steroid hormone in the SER
in muscle tissue, the SER stores calcium for CBC
what does a methylated gene mean?
methylated genes are inactive
where are 5’caps found?
mRNA
not found in DNA!
what are introns?
Introns are noncoding sections of an RNA transcript, or the DNA encoding it, that are spliced out before the RNA molecule is translated into a protein
The sections of DNA (or RNA) that code for proteins are called exons
what are exons?
The sections of DNA (or RNA) that code for proteins are called exons
where are poly(A) tails found?
mRNA
increases the stability of mRNA
not found in DNA!
what is the founder effect?
when certain areas of the world have a higher frequency of a certain allele than other area
like if two people with a disease move to an island and start reproducing then everyone there would probably have that disease and the frequency would be higher
what is disruptive selection?
also called diversifying selection
describes changes in population genetics in which extreme values for a trait are favored over intermediate values (double bell curve around 50)
in this case, the variance of the trait increases and the population is divided into two distinct groups - increases genetic variance when natural selection selects for two or more extreme phenotypes that each have specific advantages
ex. imagine a population of mice living at the beach where there is light-colored sand interspersed with patches of tall grass. In this scenario, light-colored mice that blend in with the sand would be favored, as well as dark-colored mice that can hide in the grass. Medium-colored mice, on the other hand, would not blend in with either the grass or the sand
what is stabilizing selection?
natural selection favors an average phenotype and selects against extreme variations
genetic variance will decrease
what is directional stabilization?
a population’s genetic variance shifts toward a new phenotype when exposed to environmental changes
selects for phenotypes at one end of the spectrum of existing variation
what’s the bottleneck effect?
events in which the number of individuals in a population is reduced drastically
ex. a disease wiping out a population down to 20 individuals or being hunted down to 20 individuals
you lose genetic variance
what is genetic drift?
the change in the frequency of a gene variant (allele) in a population due to random sampling of organisms
when there are few copies of an allele, the effect of genetic drift is larger, and when there are many copies the effect is smaller–> the gene pool of a small population will be significantly altered by random mutations
ex. 20 marbles in a jar –> Half of the marbles in the jar are red and half blue, and both colours correspond to two different alleles of one gene in the population –> In each new generation the organisms reproduce at random. To represent this reproduction, randomly select a marble from the original jar and deposit a new marble with the same colour as its “offspring” into a new jar. (The selected marble remains in the original jar.) Repeat this process until there are 20 new marbles in the second jar. The second jar then contains a second generation of “offspring,” consisting of 20 marbles of various colours. Unless the second jar contains exactly 10 red marbles and 10 blue marbles, a random shift occurred in the allele frequencies.
what’s the relationship between genetic drift and founder effect and bottleneck effect?
genetic drift can follow the pattern of founder effect and bottleneck effect but it can’t cause them
how is mitochondrial DNA inherited?
only from the mom
the sperm does not have any organelles
what’s transcription?
DNA to RNA
what’s translation?
RNA to proteins
what are antibiotics for?
bacteria!
NOT viruses
what influences the rate of enzyme catalyzed reaction?
1) temperature
2) pH
3) salinity
what is the replication of somatic cells?
mitosis
what’s the replication of reproductive cells?
meiosis
what is gastrulation?
during gastrulation, cell movements result in a massive reorganization of the embryo from a simple spherical ball of cells, the blastula, into a multi-layered organism
the endoderm, mesoderm, and ectoderm form
what layer of protein structure is characterized by alpha helices and beta sheets?
secondary structure
what is heart rate?
beats per minute
what is cardiac output?
CO = HR X SV
CO = (beats/minute)(liters/beat) = liters/minute
what does vasodilation or vasoconstriction do to blood flow?
vasodilation increases blood flow but decreases speed
vasoconstriction decreases flood flow but increases speed
where is oxytocin synthesized and released from?
synthesized in the hypothalamus
released from posterior pituitary
what gives rise to pseudopodia?
polymerization and depolymerization of actin
actin is a microfilament
what are intermediate filaments important for?
cytoskeleton
what are microfilaments important for?
maintaining cell shape
what are centrioles important for?
centrioles are microtubule organizing centers
what regions an antibody are involved in antigenic hormone binding?
variable region of the light chain
variable region of the heavy chain
what is the constant region of the heavy chain in an antibody involved in?
cellular recognition
what is the constant region of the light chain in an antibody involved in?
the constant region of the light chain binds tightly to the constant region of the heavy chain
if an amino acid is subjected to electrophoresis at pH = 8.5 and migrates towards the anode, what is the isoelectric point of the amino acid?
less than 8.5
the anode oxidizes aka takes electrons
if the AA moves towards the anode then it must have a net negative charge
so to be neutral, it has to be protonated and you can do that by lowering the pH
during electrophoresis, what happens to an AA with a negative charge?
it moves towards the anode to be oxidized and lose the “extra” electrons and become neutral
the pI of the AA would be lower than the current pH that it’s in because it needs to gain H+ to become neutral since it’s (-)
during electrophoresis, what happens to an AA with a positive charge?
it moves towards the cathode to be reduced and gain electrons to become neutral
the pI of the AA would be higher than the current pH that it’s in because it needs to lose H+ to become neutral since it’s (+)
what energy source do cells that use direct phosphorylation have?
creatine phosphate
does not require glucose metabolism
ATP is not the energy storage molecule used for direct phosphorylation
what modifications occur during post-transcriptional processing?
1) addition of the 5’ cap
2) splicing of exons
3) removal of introns
4) polyadenylation (poly-A tail)
what does polyadenylation do?
it occurs during post-transcriptional processing
it protects the 3’ end of mRNA from degradation
in what direction does translation occur?
translational machinery assmebles at the 5’ end of mRNA
what happens to the primary transcripts?
they are made in the nucleus and exported to the cytoplasm
what does the nucleolus do?
site of rRNA transcription and processing
the size of the nucleolus in a cell is proportional to the amount of protein produced by the cell = the more protein a cell needs, the more ribosomes it’ll have and the bigger the nucleolus will be
where are alpha cells located?
pancreas
what cells would have large a nucleolus?
cancer cells
they’re replicating quickly and have high metabolic activity
so they’re making lots of proteins and their nucleolus is where rRNA is transcribed
what types of RNA are noncoding?
tRNA and rRNA
where is trypsinogen produced?
pancreas
where is amylase produced?
salivary glands and pancreas
what is the mitral valve?
bicuspid valve
between the left atrium and right atrium
what is facilitated diffusion?
when a carrier molecule facilitates the diffusion of another molecule across a membrane along the molecules concentration gradient (not against, aka doesn’t need ATP)
