Bio/Biochem Flashcards
What is heterochromatin?
a compact, transcriptionally silent form of chromatin
found at the centromere (the chromosome region where spindle microtubules attach)
Where are phosphodiester bonds in nucleotides (RNA/DNA)?
DNA and RNA nucleotides are linked by phosphodiester bonds between the 5′ and 3′ positions of their sugar moieties and phosphate groups
What are epithelial cells?
Epithelial cells are a type of cell that lines the surfaces of your body. They are found on your skin, blood vessels, urinary tract, and organs
In the male reproductive system, leydig cells are responsible for producing what?
Androgens (i.e. testosterone)
Where is ATP synthase found in ETC?
ATP synthase is an integral membrane protein that is found/embedded on the inner mitochondrial membrane
What is the Hardy-Weinberg equilibrium equation?
1 = p² + 2pq + q²
p = dominant homozygous frequency (AA)
pq = heterozygous frequency (Aa)
q = recessive homozygous frequency (aa)
Define natural selection
the process whereby organisms better adapted to their environment tend to survive and produce more offspring
What steps in metabolism tend to be closely regulated?
highly energetically favorable or unfavorable steps
what is an arocentric chromosome?
A chromosome in which the centromere is located quite near one end of the chromosome. Humans normally have five pairs of acrocentric chromosomes.
Down syndrome is caused by an extra acrocentric chromosome (chromosome21).
How do steroid hormones enter the cell?
Steroid hormones diffuse directly through the plasma membrane of target cells and bind to receptors located in either the cytoplasm or nucleus
What is the function of kinases?
transfer a phosphate group from ATP to another molecule
Hydroxyl groups that face downards (alpha) in cyclized versions of carbohydrates face which side in their linear structure (left or right)?
Right face hydroxyl (D) will be down-faceing in a haworth projection
while left face substituents will be updard-facing in a haworth projection
What are the features of peptide hormones?
- polar
- inability to diffuse through the plasma membrane
- interact with transmembrane receptors
- hydrophilic/lipophobic
- relatively large proteins
What force primarily drives metabolic processes?
Electromagnetism
Where does the Kreb cycle occur
the mitochondrial matrix
What are the two types of RNA interference (RNAi)?
small interfering RNA (siRNA): double stranded
microRNA: single stranded
What are okazaki fragments?
Okazaki fragments are short sequences of DNA nucleotides (approximately 150 to 200 base pairs long in eukaryotes)
which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication
In amino acids, at lower pH ranges, amines carry a ___ charge while carboxylic acids carry a ____ charge
In amino acids, at lower pH ranges, amines carry a positive charge while carboxylic acids carry a neutral charge
Where is vasopressin released/produced?
The pituitary gland
Through which process can multiple proteins stem from a single pre-mRNA transcript?
Alternative splicing
What are prosthetic groups?
coenzymes that are tightly bound to the enzyme they assist.
typically located at or near an enzyme’s active site
they tend to play a specific role in the catalytic mechanism that occurs in the active site
what is interphase?
The cell cycle is a four-stage process in which the cell increases in size (gap 1, or G1, stage), copies its DNA (synthesis, or S, stage), prepares to divide (gap 2, or G2, stage), and divides (mitosis, or M, stage)
altogether, this is known as interphase – the stage of the cell cycle that occurs between rounds of cell division (mitosis)
What bonds creates secondary protein structures?
hydrogen bonding between backbone atoms
what kind of amino acid is most likely to become phosphorylated?
an amino acid that contains an -OH group on thier side chains
(i.e. Serine (S), Threonine (T), Tyrosine (Y))
What is the leading strand in DNA replication?
DNA is added to the leading strand continuously, one complementary base at a time
What determines vascular resistance?
the size of individual vessels and the organization of the vascular network
Changes in vessel diameter as the blood flows through the various vessel types are important for regulating blood flow within an organ, as well as for regulating arterial pressure.
Highest resistance
Arterioles
Capillaries
Arteries
Venules and veins
lowest resistance
the size change from arterioles to capillaries is so large, so there is a lot of resistance at the aterioles. **In addition to the pressure that comes from arteries/arterioles deriving from the heart, this makes them higher in resistance than venules/veins
what is the function of a phosphatase enzyme?
A phosphatase is an enzyme that removes a phosphate group from a protein
how many chromosomes do people usually have?
46 chromosomes total
22 autosomal pairs
1 pair of sex chromosomes
What are the products of the krebs cycle ( tricarboxylic acid cycle)?
carbon dioxide molecules
ATP/GTP
Reduced forms of NADH and FADH2 (NAD+ and FAD are reduced)
What is the charge of histidine at physiological pH (~7.4)?
predominantly uncharged, or neutral
(*histidine is normally considered basic with (+) charge)
What happens at the end of oxidative phosphorylation?
ADP is phosphorylated to porduce ATP
Name three hormones released by the adrenal cortex
- aldosterones
- mineralocorticoid that is secreted by the adrenal cortex in response to low blood pressure and volume
- cortisol
- glucocorticoid cortisol in response to stress and low blood glucose levels
- androgens
- hormones that play a role in male traits and reproductive activity
What creates the tertiary structure in proteins?
Side chain interactions
the complex interactions between R groups of its constituent amino acids. These interactions include hydrogen bonding, ionic bonding, covalent bonding, and hydrophobic attractions
What is Z-DNA?
Z-DNA is left-handed and often found among methylated DNA sequences
What is the role of glycoproteins in the plasma membrane?
Glycoproteins are often involved in cell recognition, such as with major histocompatibility complexes, and communication processes
What does cristae provide for the innermembrane of the mitochondria?
it greatly increases the surface area
What are secondary structures of proteins?
segments of the protein chain that fold into regular repeating units held together by hydrogen bonding between amino and carbonyl atoms of the protein’s backbone <em>(not side chain)</em>
What is the primary responsiblity of the nucelosome?
located within a eukaryotic nucleus,
it is primarily responsible for ribosome synthesis and assembly
During an action potential, calcium is moving ____ the cell
inside the cell
Action potentials open voltage-sensitive calcium channels in excitable cells, leading to an influx of calcium ions
What is cleavage division/mitosis?
It is the repeated mitotic division of the zygote resulting in an increasing number of cells
(but it does NOT result in an increase or change in the size/volume of the zygote)
When pH is lower than the pKa value, the acid is likely to be ____
protonated
(in its acidic form)
What 3 substances inhibit the final step in glycolysis?
- acetyl-CoA
- long chain fatty acids
- ATP
What is gabriel synthesis?
a chemical reaction that transforms primary alkyl halides into primary amines (amino acid synthesis)
Is ATP an electron carrier?
No
The following image showcases organs that are a part of what system?
The endocrine system
What type of vitamins are typically harmless at high levels?
water soluble vitamins
When consumed in excess, it is not typically dangerous because the body can easily eliminate it in the urine
these include vitamins B and C
What is glycosyltransferase?
An enzyme that catalyzes the formation of glycosidic linkages
What three structures are considered part of the brain stem?
The midbrain, pons, and medulla oblongata are collectively referred to as the brainstem.
The brainstem connects to the spinal cord.
Why is the respiratory system part of the innate immune system?
Hairs in the nasal cavity and mucus from the respiratory tract stop pathogens in their tracks, trapping microbes and particulate matter that can be expelled either by sneezing or by cilia pushing mucus upward to be coughed out or swallowed.
The respiratory tract also produces its own antimicrobial proteins, called defensins, that have broad-spectrum antimicrobial activity against bacteria, fungi, and viruses.
What is adaptation?
evolution on a smaller scale
It occurs when two populations of the same species adapt to slightly different environmental niches, but they are still capable of mating and reproducing offspring
Which amino acids contain sulfur, is nonpolar?
Methionine, Met, M
Cysteine, Cys, C
Why does the first step of gluconeogenesis take place in the mitochondria before it continues onto step two in the cytosol?
Because the first step of gluconeogenesis occurs in mitochondria and glycolysis takes place in the cytoplasm, the two cycles are spatially separated and can be regulated more easily.
Pyruvate coming out of glycolysis will not be converted into PEP, because the enzyme that converts pyruvate to oxaloacetate is located inside mitochondria
What type of interaction is found between bases in DNA?
Hydrophobic interactions
(The nitrogenous bases of DNA interact due to hydrophobic interactions between the planar aromatic bases)
What are the glial cells and what do they do?
What is the function of proteases?
Proteases are the enzymes responsible for catalyzing peptide bond hydrolysis (protein breakdown)
(which is normally a physiologically slow process)
What is mixed inhibition?
the inhibitor can either bind the free enzyme at an allosteric site (noncompetitive) or bind the Enzyme-Substrate (E-S) complex (uncompetitive)
What are the 5 steps in for generating recombinant DNA? (plasmid + bacteria)
- Synthesize a gene sequence (or “insert”) with the proper restriction sites.
- Digest the insert and whatever relevant vector components (such as a plasmid) with corresponding restriction enzymes, which cleave at the designed restriction sites.
- Ligate the vector and the insert together with DNA ligase.
- Insert plasmid into the bacteria to be replicated.
- Select for and isolate bacteria containing the plasmid of interest by some means (usually a reporter gene or by treatment with antibiotics).
How does ADH help raise blood pressure/blood volume?
Helps with water reabsorption
What is a promoter?
A short sequence upstream of its target gene that serves as the initial binding site for RNA polymerase to initiate transcription
promoters tend to be in close proximity upstream of target genes.
Under what conditions can steps in the synthetic sequence of gabriel and stecker synthesis be catalyzed?
acidic
Which direction is mRNA protein translated? (read)
5’ to 3’
The corpus luteum produces what hormones?
estrogen and progesterone
What is B-DNA?
It is slightly less compact than A-DNA
DNA perfers to occur in the B form under physiological conditions in the cell
How does ADH, ANP, and aldosterone deal act on fluid loss/retention and plasma osmolarity?
ADH is released by the posterior pituitary in response to low blood pressure and high plasma osmolality. It directly increases the permeability of the collecting duct to water by upregulating the expression of aquaporin channels, which allow water to flow along its concentration gradient from the kidney filtrate back into the bloodstream. ADH initially reduces blood osmolality because it increases water absorption without affecting solute reabsorption.
ANP is produced by muscle cells of the heart, or cardiomyocytes, and it is released in response to high blood volume. It decreases sodium reabsorption in the distal convoluted tubule and collecting duct. It also increases the filtration rate in the glomerulus to speed up water excretion, and it inhibits aldosterone release. Therefore, it works to lower blood pressure and volume by promoting fluid loss.
Aldosterone is secreted by the adrenal cortex in response to low blood volume. It travels to the kidney, where it promotes sodium reabsorption in the distal tubule and collecting duct of the nephron. As plasma osmolality increases, in the presence of ADH, water follows its gradient from the kidney filtrate into the bloodstream by osmosis, increasing blood volume and pressure.
What is a palindromic sequence?
A palindromic sequence is a sequence made up of nucleic acids within double helix of DNA and/or RNA that is the same when read from 5’ to 3’ on one strand and 5’ to 3’ on the other, complementary, strand
Acetylcholine is polar or nonpolar neurotransmitter?
polar
interacts with cell receptors
What is the function of GLUT1?
It is expressed throughout the body and is responsible for baseline cellular glucose intake
most often expressed in response to low blood sugar levels
<em>insulin independent</em>
<em>(i.e. When cellular levels of glucose are low, the expression of GLUT1 is upregulated)</em>
What is the equation for catalytic efficiency for enzymes?
Kcat/Km
or (Vmax/[Et]) / Km
What are the ribosomes found in bacteria?
Prokaryotic 70S ribsosomes
containing 50S and 30S subunits
What are the basic steps of gabriel
What is the difference between a template and coding strand in transcription?
Template (antisense) strand: read by RNA polymerase
Coding (sense) strand: strand NOT read by RNA polymerase. complementary to template strand. Nearly identical to synthesized RNA (exchange T for U)
Which amino acid could not rotate plane-polarized light?
Glycine (Gly, G) – because it is a chiral molecule and cannot rotate plane-polarized light by definition
What binds carbohydrates?
glycosidic bonds
What does the endoplasmic reticulum do?
protein modification site post-synthesis
What are the two main functions of DNA polymerase II?
- Repairs DNA
- Proof-read DNA
Where is atrial natriuretic peptide (ANP) hormone released from?
Muscle cells in the heart secrete atrial natriuretic peptide (ANP), which is released in response to high blood volume and helps decrease blood pressure.
What two amino acids are NOT gluconeogenic substrates? (can be converted into pyruvate in preparation for gluconeogenesis)
Leucine
Lysine
What do reducing agents do?
Reducing agents reduce disulfide bonds
In the context of an operon, what is the operator?
operator is the sequence bound by a repressor, which inhibits gene expression
What is a ogliopeptide?
a peptide composed of a few (2-20) amino acid residues
What are glycosidic linkages?
Glycosidic linkages are covalent carbon/oxygen/carbon linkages formed between two sugar molecules
the glue that holds together disaccharides/polysaccharides
What hormone prevents the loss of existing endometrium?
Progesterone
(key hormone released by the corpus luteum)
What structure exists in proteins consisting of two or more identical or different polypeptide chains (subunits)?
Quarternary structure
What is the function of lyases?
catalyze non-hydrolytic cleavages
they cleave bonds but do not use hydrolysis
catalyzes the breaking (an “elimination” reaction) of various chemical bonds by means other than hydrolysis (a “substitution” reaction) and oxidation, often forming a new double bond or a new ring structure
What feedback loop leads to enzyme activation?
positive feedback tend to activate enzymes so that they produce more product
Do prokaryotes contain a mitochondria?
Prokaryotes do not have membrane-bound organelles like mitochondria
On which end of the amino acid are new amino acids added in the translation process?
C terminus (carboxyl end)
Which experiences a higher activation energy:
exergonic reaction s or endergonic reactions?
endergonic reaction
Generally speaking, all reactions require at least a little activation energy because the transition state is at a higher energy level than the reactants and products.
However, for a given chemical process, the endergonic reaction will require more activation energy than the exergonic reverse reaction because the activation energy of an endergonic process is the sum of the energy difference between the products and reactants and the activation energy of the exergonic reaction.
Is it possible to use the second equivalence point in a titration to calculate the concentration of the analyte solution?
Yes.
there is always a fixed ratio of acid to base added at the second equivalence point
i.e. for every 1 molecule of a diprotic acid, 2 molecules of a base (like HO-) would be present to deprotonate the analyte
What is the main driver for protein breakdown in the stomach?
The protease, pepsin
Why does gluconeogensis occur?
- maintain blood glucose
- replenish glycogen in the liver
use gluconeogensis when the body has to make glucose from scratch
What are apoenzymes?
enzymes that lack important cofactors
because these cofactors are required for catalysis, apoenzymes are nonfunctional
What is the function of ligases?
join molecules together with covalent bonds
What is the start codon and what amino acid does it encode?
AUG
Methionine (Met, M)
Under what mechanism is DNA replicated?
Semiconservative
In development, what happens during gastrulation?
Formation of the endo-, meso, and ectoderm
the three primary germ layers
After leaving the ovary where does an oocyte travel next?
The abdominal cavity
The oocyte starts in the ovaries where it was developing and maturing, then passes through the abdominal cavity for a very brief moment before entering the Fallopian tube
What is the function of GLUT4 and where is it expressed?
expressed in cardiac muscle, skeletal muscle, and adipose tissue
GLUT4’s major function is to bring glucose into the cell in order to store it as glycogen or triglycerides when there is a surplus of glucose in the blood
What hormone encourgaes the proliferation of the endometrium?
Estrogen
How would an enzyme alter the local pH so that a reaction could occur?
if an active site had a significant amount of acidic residues, this would decrease the local pH, encouraging acid catalyzed chemical reactions
<em>*the enzyme is not changing the pH of the biological system overall, just temporarily manipulating the active site</em>
What are spermatids?
an immature male sex cell formed from a spermatocyte that can develop into a spermatozoon without further division
What does Km ultimately measure?
It can be used to measure the affinity that an enzyme has for its substrate (the phenomenon that some enzymes interact more readily with their substrates than others)
It provides a measure of how much enzyme we need to get halfway to the saturation point
Dissolution reactions increase or decrease presssure?
All dissolutions increase pressure.
Name three different types of glycosidic bond formations?
O-glycosidic bonds (involved in the formation of sugars)
N-glycosidic bonds (nitrogen nucleophile)
S-glycosidic bonds (attaching sugars to cysteine residues)
The smooth endoplasmic reticulum (ER) is a _____ - _____ organelle
membrane-bound
What gonadotropic hormone acts on Sertoli cells?
Follicle stimulating hormone (FSH)
promotes spermatogenesis in men
stimulates follicle growth in women
What is bradycardia?
Bradycardia is a slower than normal heart rate
heart beats fewer than 60 times a minute
what is a prosthetic group?
a type of coenzyme that is tightly bound to the enzyme itself
what is a conserved sequence?
DNA sequences that are common among different species, phyla, or even kingdoms are called conserved sequences
Conservation indicates that a sequence has been maintained by natural selection
Conserved sequences tend to remain that way due to the fact that they code for a vital function that is common among disparate species
What can break peptide bonds?
Hydrolysis reactions
What is the function of oxidoreductases
catalyze oxidation-reduction reactions (i.e. the transfer of electrons)
What is divergent evolution?
Similarities between species that have diverged are due to their common origin, so such similarities are homologies
What is binary fission?
process through which asexual reproduction happens in bacteria
What is the cytosol?
cytosol is the fluid contained in the cell cytoplasm
What are the 5 conditions of the Hardy-Weinberg equilibrium?
- no mutation
- no gene flow
- large population size
- random mating
- no natural selection
True or false: Only some monosaccharides can be reducing sugars
false
all monosaccharides are reducing sugars.
i.e. Tallose, Mannose, Fructose, Glucose, etc
What is the relationship between molarity and normality?
What are the 3 stop codons?
UAA
UAG
UGA
What is the average molecular weight of an amino acid?
110 g/mol
or 110 Da
What 8 organs are part of the endocrine system?
How do prokaryotic cells,such as bacteria, achieve locomotion?
bacteria may have flagella
What is a coenzyme?
organic cofactors that help enzymes catalyze reactions
How does histone deacetylases affect gene expression?
A sugar that contains a N-glycosidic bond at the anomeric carbon is a reducing or non-reducing sugar?
Non-reducing
the N-glycosidic bond at the anomeric carbon precludes any further ring opening
What is polycistronic?
a single mRNA sequence may encode multiple proteins
Prokaryotic mRNA is often polycistronic
What are basal ganglia?
The basal ganglia are a series of subcortical structures that take part in a variety of functions, including modulating voluntary motor control.
They are located in the cerebrum
What is the major contributor to ATP’s ability to store energy?
the electric potential energy contained in the bunched-up negative charges in the phosphate groups
How does atrial natriuretic peptide (ANP) hormone lower blood pressure/blood volume?
decreases sodium reabsorption which promotes fluid loss
Does fetal hemoglobin have a higher or lower oxygen affinity than adult fetal globin?
Higher
so it can steal/grab some oxygen from mother during pregnancy
What is a noncompetitve inhibitor?
an inhibitor that interacts with the enzyme allosterically – a site other than the active site.
This inhibitor can interact with an enzyme regardless of whether it has bound to a substrate
What is the lineweaver-burk plot?
(a double reciprocal plot)
a graphical representation of enzyme kinetics
The lateral geniculate body and the superior colliculus are neural components that play a key role in what?
processing vision
The lateral geniculate body and the superior colliculus are key relay points for the visual pathway that ultimately terminates in the primary visual cortex in the occipital lobe
What is the “post office” of the cell?
(packing proteins to leave the cell)
Golgi apparatus
What happens to the Km and Vmax of an enzyme when there is a uncompetitive inhibitor?
reduce Vmax
reduce Km
What is the Wolffian duct?
the embryonic structures that form the male internal genitalia. These ducts develop in both the male and female embryo. However, in the female they subsequently regress, whereas in the male they are stabilised by testosterone
What are holoenzymes?
enzymes that contain all elements they need in order to function, including any coenzymes or inorganic cofactors
What are the general functions of the following glial cells:
Astrocytes transport nutrients, such as glucose, and contribute to forming the blood brain barrier.
Oligodendrocytes create myelin in the central nervous system, the primary insulation material that wraps around axons.
Microglia work similarly to macrophages, defending neuronal cells from foreign pathogens.
Ependymal cells secrete and circulate cerebrospinal fluid, which lubricates and protects the central nervous system.
What are the effects of pH, CO2, and temperature on oxygen affinity in red blood cells?
High pH corresponds with a left shift (increase affinity)
high temperature corresponds with a right shift (decrease affinity)
high CO2 correspond with a right shift (decrease affinity)
What are the jobs of smooth endoplasmic reticulum (ER)?
lipid synthesis, calcium ion storage and metabolism, and detoxification
in physiological conditions (pH 7.2 -7.4), what is the charge on the N-terminus of an amino acid/protein?
the N-terminus tends to exist in the from of a positively charged -NH3+ (protonated state)
while th C-terminus is likely to be negatively charged because it is in its deprontated state
PH > pKa –> deprotonated
PH < pKa –> protonated
What two types of interactions are mainly seen between enzymes and substrates?
polarity
sterics-based interactions
(noncovalent)
What are the four types of bonsd in teriary protein structures?
There are four types of tertiary interactions:
hydrophobic interactions,
hydrogen bonds,
salt bridges,
and sulfur-sulfur covalent bond
What two macronutrients are absorbs in the enterocytes of the small intestine via secondary active transport?
amino acids (proteins)
monosaccharides (carbohydrates)
What causes negative pressure breathing?
inhalation is driven by negative pressure breathing in which the pressure inside the lungs is less than the atmospheric pressure.
- the muscular diaphragm beneath the lungs contracts, moving downward and causing
- the thoracic cavity to expand and the intrapleural pressure to become more negative. This causes
- the lungs to expand. Increased lung volume
- reduces the alveolar pressure, which causes
- air to flow into the lungs to maintain equilibrium with ambient air pressure.
What is the corona radiata?
a layer of follicular cells on the secondary oocyte
What DNA is most abundant in humans?
B-DNA
Are most dissolution reactions exothermic or endothermic?
most dissolutions are endothermic, and require heat input.
Exothermic dissolutions, which release heat, are rarer.
All dissolutions increase pressure.
How does histone acetyltransferases affect gene expression?
What are nucelic acids?
a complex organic substance present in living cells, especially DNA or RNA, whose molecules consist of many nucleotides linked in a long chain
What are kinetochores?
protein complexes at the chromosomal centromere and bind to microtubule spindle fibers in the mitotic spindle
Where are ribosomes found?
Rough ER
Cytoplasm (free-floating ribosomes)
Where are sphingolipids found in the plasma membrane?
in lipids rafts with cholesterol in the form of sphingomyelin
What determines the development of reproductive organs in a fetus?
The presence or absence of androgens
<em>(later in life, estrogens contribute to the development of secondary sex characteristics as well as play an important role in the hormonal control of reproduction, but they do not control the development of reproductive organs in the fetus)</em>
In what direction is the structure of a protein conventionally written?
N-terminus to the C-terminus
Which direction are proteins synthesized?
Proteins are synthesized from N to C terminus
What is a common mnemonic to memorize the pathway sperm take through the male reproductive system?
SEVEN UP
S - seminiferous tubules
E- epididymis
V- vas deferens
E- ejaculatory ducts
N- The “N” in the mnemonic stands for “nothing” and is used to help the mnemonic fit together
U- urethra
P- penis
What is organogenesis and when does it occur?
Development of major organs during the first trimester of pregnancy
What is the function of:
RNA polymerase I
RNA polymerase II
RNA polymerase III
Acidic and basic amino acids have how many pKa points?
3 pKa points
1 for -COOH
1 for -NH3+
1 for side chain
What are gram-positive bacteria?
Gram-positive bacteria have a thick, peptidoglycan-rich cell wall that readily traps the Gram stain within its cross-linked polymers, turning Gram-positive cells a deep shade of purple
such a bacterium lacks a second membrane on the outside of its cell wall. This quality makes Gram-positive cells especially sensitive to antibiotics that target peptidoglycan
(peptidoglycan = carbohydrate polymer + amino acids)
What is the two main difference between bacteria and viruses (archaea)?
Viruses are not living organisms, whereas bacteria are.
Viruses are only “active” within host cells which they need to reproduce, while bacteria are single-celled organisms that produce their own energy and can reproduce on their own
What are spermatozoa?
A mature sperm cell (has mobility)
What is strecker synthesis?
a method for the synthesis of amino acids by the reaction of an aldehyde with ammonium chloride in the presence of potassium cyanide
what are the 4 stages of mitosis?
Prophase: chromosomes start to condense, the mitotic spindle begins to form, the nucleolus disappears, and nuclear envelope breaks down and releases the chromosomes
Metaphase: All the chromosomes align at the metaphase plate (not a physical structure, just a term for the plane where the chromosomes line up)
Anaphase: the sister chromatids separate from each other and are pulled towards opposite ends of the cell
Telophase: the mitotic spindle is broken down into its building blocks, two new nuclei form – one for each set of chromosomes, nuclear membranes and nucleoli reappear, the chromosomes begin to decondense and return to their “stringy” form
*cytokinesis is the division of the cytoplasm to form two new cells, overlaps with the final stages of mitosis. It may start in either anaphase or telophase, depending on the cell, and finishes shortly after telophase
Can steroid or peptide hormones alter gene expression within target cells?
Steroid hormones affect gene expression inside target cells
sterpod hormones may take a bit longer than peptide hormones but they promote long-lasting changes, whereas peptide hormones produce more short-term changes
What is the relevance of sterols in the context of the plasma membrane?
Sterols (specifically, cholesterol) are the plasma membrane’s second main lipid component
modulate the fluidity of plasma membranes by clustering with sphingomyelin to form structures known as “lipid rafts”
What does calcitonin do?
Calcitonin reduces the concentration of calcium in the bloodstream by reducing calcium absorption in the intestines, promoting calcium storage in bone, and increasing urinary excretion of calcium
it “tones” down calcium
What is molecular clock analysis?
commonly used to estimate when speciation events occurred in the past
assumes that genes mutate/random errors accumulate at a relatively constant rate
What binds triglycerides and where?
Triglycerides are held together at the glycerol backbone by ester bonds
In the male reproductive system, the seminal vesicles secrete what?
seminal vesicles secrete nutrients into seminal fluid
What is differential fitness?
survival and reproduction rates vary between individuals
Not every individual in a population will have the same survival or reproductive rate, and this enables traits to be selected for or against
What is the function of DNA gyrase?
DNA gyrase (a topoisomerase) reduces supercoiling as the double helix unwinds by creating incisions in the sugar-phosphate backbone in order to relax the DNA
(like when you try to unwind two strands from string, you get super coiling at the ends. DNA gyrase prevents that by allowing the DNA to turn at the incision mark before joining it back together)
What two hormones help alleviate low blood pressure/low blood volume?
ADH (vasopressin)
Aldosterone
What enzyme unwinds DNA?
Helicase
What 4 forces interact in teritary and quarternary protein structures?
- hydrogen bonds
- ionic bonds
- hydrophobic interactions (drives protein folding)
- covalent bonds (disulfide bonds)
Which amino acid breaks up structural motifs in the secondary structure of proteins?
Proline (Pro, P)
because its side chain connects back to the amine group of the amino acid backbone itself
what is an operon?
An operon is a coordinated unit of DNA that contains genes that are regulated and transcribed together in prokaryotes
In what direction does DNA polymerase III read the DNA strand?
3’ to 5’
(new DNA is synthesized in the 5’ to 3’ direction)
What three sub-classes of steroid hormones are released from the adrenal cortex?
- glucocorticoids
- i.e. cortisol
- mineralocorticoids
- cortical sex hormones
Why can proline (p) have the ability to break up secondary protein structures?
Proline has the unique property of breaking up secondary structure motifs through its unique ring structure that incorporates the backbone of the amino acid itself
What hormone is associated with long term stress?
Cortisol
What does polyadenylation do for mRNA?
Polyadenylation protects mRNA from degradation, by targeting the 3’ end
How does glucose affect gene expression of the prokaryotic lac operon?
Low glucose levels means higher levels of available cAMP
cAMP binds to the Cap-Binding site of the lac operon, which then enhances/stimulates transcription and expression of the gene
↓ glucose = ↑ cAMP = ↑ gene expression
What is homotropic regulation?
homotropic regulation is when a molecule serves as a substrate for its target enzyme, as well as a regulatory molecule of the enzymes activity
For example, O2 is a homotropic allosteric modulator of hemoglobin
What is the basic logic of metabolism in life on earth?
use redox (oxidation/reduction) reactions to shuttle electrons around in order to generate molecules that can store energy
What two organs regulate blood glucose? (i.e. gluconeogenesis)
- liver
- store most of the body’s extra glucose, also responsible for generating a lot of new glucose molecules through gluconeogenesis.
- kidneys
- The kidneys reabsorb glucose from the urine and even create some of their own glucose through gluconeogenesis
What does protein folding depend on?
nonpolar amino acids grouping together to avoid unfavorable interactions with polar solvent molecules
What is the purpose of autonomic ganglia?
Autonomic ganglia serve as intermediates for the neural impulse of the central nervous system
they are intermediate junctions between the central nervous system and target organs
what are lymphocytes?
Lymphocytes are a common class of leukocytes, and they are the main types of cells found in the lymph
lymphocytes include T-cells, B-cells, and natural killer cells
*Lymph is the fluid that flows through the lymphatic system, a system composed of lymph vessels and intervening lymph nodes whose function, like the venous system, is to return fluid from the tissues to the central circulation
In translation, what are the functions of the A site, E site, and P site
A site: Accepts the incoming aminoacyl-tRNA complex.
P site: Forms a peptide bond between a new incoming amino acid and the growing peptide chain
E site: Allows the uncharged tRNA molecule to leave the ribosome.
Going from outside to inside, list the major features of the mitochondria
outermembrane
intermembrane space
innermembrane
matrix
What are the two types of polysaccharides that make up starches, and which one is the dominant form?
20-30% Amylose (linear glucose polysaccharide: alpha-1,4 bonds)
70-80% Amylopectin (branched glucose polysaccharide: alpha-1,4 bonds + alpha-1,6 bonds)
what are the three viable autosomal trisomies?
Trisomy 21, 18, and 13
How does methylation affect gene expression?
methylation deactivates/silences gene sequences, downregulating expression
(bind to the promoter region, which blocks transcription)
important in epigentics (environment + genes)
occurs in both eukaryotes and prokaryotes
What is the function of transferases?
transfer a functional group between molecules
What are fatty acids and what is their molecular structure?
Fatty acids are the building blocks of the fat
Fatty acids are long alkyl chains that terminate in a carboxylic acid group.
is competitive, non-competitive, and uncompetitive inhibition reversible or irreversible?
these three types of inhibition are considered reversible becuase the inhibitor can dissociate from the enzyme or enzyme-substrate complex
What is a substrate analog?
Substrate analogs (substrate state analogues), are chemical compounds with a chemical structure that resemble the substrate molecule in an enzyme-catalyzed chemical reaction.
Substrate analogs can act as competitive inhibitors of an enzymatic reaction
What is the function of the thalamus?
The thalamus primarily serves to relay sensory and motor signals to the cerebral cortex
Where does the krebs cycle occur?
The matrix of the mitochondria
A northern blot measures levels of ___
RNA
thickness of band –> expression levels
location of band –> size of RNA
How does the trp operon found in prokaryotic genes function?
Negative repressible
its expression is repressed by binding a repressor to the operator
What is renin?
Renin is an enzyme that functions within the renin-angiotensin-_aldosterone_ system (RAAS), which works to increase blood pressure. Specifically, renin cleaves angiotensin I to angiotensin II.
What are three functions of the hypothalamus?
- Communicating with the nervous system
- The hypothalamus is considered the bridge between the endocrine system and the nervous system.
- It oversees many autonomic activities, such as body temperature, metabolism, fatigue, and sleep.
- Regulation of metabolism
- Stimulating hormone release
- The hypothalamus stimulates the release of hormones by the anterior pituitary gland
- The anterior pituitary responds to these releasing factors from the hypothalamus by releasing its own set of hormones
What is a pyranose?
a collective term for saccharides that have a chemical structure that includes a six-membered ring consisting of five carbon atoms and one oxygen atom
What two hormones raise blood calcium levels?
- Calcitriol
- promoting calcium absorption from the gastrointestinal tract, reducing the excretion of calcium in urine, and stimulating bone resorption via osteoclast activation
- parathyroid hormone (PTH)
- stimulates bone resorption, the process through which osteoclasts break down bone and release calcium into circulation
What is the epitope of an antigen?
the site on an antigen that is recognized by an antibody is known as the epitope
The trachea is lined by a ____ ?
ciliated epithelium (cilia)
moves mucus, particulate matter and microbes upward to be expelled
What happens to the Km and Vmax of an enzyme when there is a competitive inhibitor?
competitive inhibitors result in an increased Km, as more substrate is required to reach the same enzyme velocity,
but Vmax is unchanged because maximal enzyme velocity can be reached if enough substrate is added
What is a polypeptide?
polypeptide is a long, unbranched chain of amino acids
What is speciation?
Speciation occurs when two organisms undergo enough genetic change to become reproductively isolated
the formation of new and distinct species in the course of evolution
What is one of the final steps of garbriel synthesis?
decarboxylation
What is the difference between GLUT2 and GLUT4?
GLUT2 is insulin independent
GLUT2 is expressed in pacreatic beta cells, liver cells, and some kidney cells
GLUT4 is insulin dependent (high insulin = GLUT4 upregulation)
GLUT4 is expressed in cardiac muscle, skeletal muscle, and adipose tissue
What is competitive inhibition?
competitive inhibition uses an inhibitor that binds to the active site and blocks the substrate from attaching
What are the stages of a fertilized egg cell?
- zygote
- Morula (16 cell stage)
- Blastocyte
- Gasturla (formation of endo/meso/ectoderm)
- Neurula (development of the neural system)
What are fibroblasts?
A fibroblast is a type of biological cell that synthesizes the extracellular matrix and collagen, produces the structural framework (stroma) for animal tissues, and plays a critical role in wound healing
What is the relationship between repressors and silencers in eukaryotic gene expression?
silencers are regions located either upstream or downstream (or farther) of their target genes
repressors bind to silencers to downregulate transcription
Aldesterone acts on what cells in order to increase blood pressure? (2)
Aldosterone promotes sodium retention in cells of the distal convoluted tubule and collecting duct
what is the primary purpose of the acidic conditions found in the stomach?
Activate the molecule pepsin from the inactive pepsinogen to break down protein (peptide bond breakdown)
What accessory protein carries vesicles/substances from the center of the cell to the cell’s edge?
Kinesins
What happens to the Km and Vmax of an enzyme when there is a mixed inhibitor?
Vmax always decreases
if the inhibitor prefers binding to the enzyme at an active site, Km increases
if the inhibitor prefers binding to the E-S complex, Km decreases*
*(similar to the effect seen in uncompetitive inhibition)
What are the 3 digestive functions of the hormone Cholecystokinin (CCK)?
- stimulate the release of bile from the gallbladder
- stimulate the pancreas to release digestive enzymes into the duodenum
- inhibits appetite
How do prokaryotic cells contain DNA?
B/c they do not have internal organelles, other than ribosomes, DNA is free-floating in the cytosol
What are the three highly regulated steps in the TCA cycle?
- Acetyl-CoA + Oxaloacetate –> citrate + CoA-SH
- Isocitrate + NAD+ –> alpha-ketoglutarate + NADH
- Alpha-ketoglutarate + NAD+ –> succinyl CoA + NADH + CO2
What is lactose?
A disaccharide (foud in diary products)
glucose + galactose
β- 1,4 glycosidic bond
What is conjugation?
a special plasmid (fertility factor) is transferred between two cells
a major cause to anitibiotic resistance
What organelle is associated with lipid digestion?
Lysosomes
What are three hormones that regulate hunger?
- Leptin
- promotes feelings of fullness (or satiety) after a meal
- It is secreted by adipocytes in response to increased triglyceride storage.
- Ghrelin
- stimulates appetite
- It is secreted by specialized cells in the upper stomach and pancreas when the stomach is empty
- Cholecystokinin (CCK)
- functions in both digestion and appetite maintenance
- High levels of cholecystokinin inhibit appetite after a meal
- As a digestive hormone, it stimulates the secretion of digestive enzymes from the pancreas and bile from the gallbladder.
What is the primary evolutionary measure of fitness?
Reproduction
What is flagellin?
protein flagellin is only a component of prokaryotic flagella
Where are most tropic hormones produced?
the anterior pituitary
How do reversible inhibitors interact with enzymes?
Reversible inhibitors interact noncovalently with enzymes
completely preventing the inhibited enzyme molecule from functioning
What is the cortical reaction in fertilization?
The cortical reaction is a process initiated during fertilization by the release of cortical granules (green dots) from the egg, which prevents polyspermy, the fusion of multiple sperm with one egg
What is the difference between normal-phase HPLC and reverse-phase HPLC (high performance liquid chromatography)
Normal-phase HPLC (known previously as high pressure liquid chromatography) the stationary phase is polar while the mobile phase is a relatively nonpolar solvent
in reverse phase HPLC, the stationary phase is nonpolar and the mobile phase is polar
in HPLC, the mobile phase is passed through a solid absorben material under high pressure, which allows for a faster and more precise separation of compounds in the mixture
what enzyme performs a 3’-5’ exonuclease activity mechanism?
DNA polymerase
it uses this mechanism to excise mismatched bases and replace them with the correct base at that position
What is RNA interference (RNAi)?
a biological process in which non-coding RNA molecules are involved in sequence-specific suppression of gene expression
Is allosteric binding covalent or nonconvalent?
Noncovalent
What is a uncompetitve inhibitor?
this inhibitor interacts with the enzyme substrate (E-S) complex at an allosteric site
it prevents an enzyme from letting go of a substrate that it has bound
Do covalent bonds shift in their stability to changes in pH?
No
What 5-carbon sugar is found in the structure of DNA?
deoxyribose
What are substrate analogs?
Substrate anaglogs act as competitive inhibitors of the enzymes they targert
What does the lac operon code for?
This operon contains genes coding for proteins in charge of transporting lactose into the cytosol and digesting it into glucose (lactose metabolism)
This glucose is then used to make energy.
In the male reproductive system, the cremaster muscle is responsible for what?
The cremaster muscle contracts to shorten the distance between the testes and the body
On a cold day, an unclothed human adult male would find that his scrotum has moved closer to his body in order to retain more heat
The cremaster muscle relaxes to lengthen the distance between the testes and the body
On a hot summer day, an adult male would find that his scrotum has moved further away from his body in order to dissipate more heat
What 5-carbon sugar is found in the structure of RNA?
Ribose
Leydig cells are activated by what gonadotropic hormone?
Luteninizing hormone (LH)
causes males to produce testosterone
causes females to ovulate
What happens to the Km and Vmax of an enzyme when there is a noncompetitive inhibitor?
reduce Vmax
do not affect Km
What is the molecular structure of carbion dioxide?
What hormone alleviates high blood pressure/high blood volume?
atrial natriuretic peptide (ANP) hormone
What is the lysogenic stage in transduction?
The lysogenic cycle is a dormant state during which viral DNA is incorporated into the host genome to be activated later in the lytic stage
What are catecholamines?
any of a class of aromatic amines that includes a number of neurotransmitters such as epinephrine and dopamine
What is sucrose?
A disaccharide (table sugar)
⍺-glucose + β-fructose
A southern blot measures levels of ___
DNA
What are ganglia?
They are part of the peripheral nervous system and carry nerve signals to and from the central nervous system.
What is mutarotation?
Mutarotation involves breaking a covalent bond at the anomeric carbon and forming a new one with the hydroxyl group pointing in the opposite direction. This allows for the interconversion between alpha and beta anomers, as shown below.
What are floppases?
enzymes that move phospholipids from the inner leaflet to the outer leaflet
Genetic drift has a greater effect in (size) populations
small populations
What is a heterodimer?
protein complexes that consist of two different subunits
What hormone stimulates ovulation?
Luteninizing hormone (LH)
Where is estrogen produced in females?
-
the follicle
- (the granulosa cells of the ovarian follicle produce estrogen)
-
corpus luteum
- (once ovulation occurs, ruptured follicle becomes a corpus luteum ‘yellow body’ and continues to produce estrogen until it degenerates into a body of scar tissue known as corpus albicans ‘white body’)
- and the placenta
- (later in pregnancy)
What is a viral envelope?
A viral envelope is the outermost layer of many types of viruses. It protects the genetic material in their life-cycle when traveling between host cells. Not all viruses have envelopes.
The envelopes are typically derived from portions of the host cell membranes, but include some viral glycoproteins
What makes ATP hydrolysis so energetically favorable?
There is a concentration of negative charges on the phosphates in ATP.
These negative charges on the phosphates contribute to the high energy of the phosphoanhydride bonds connecting them.
Breaking these bonds will lead to a release of energy and stabilization of the negatively charged phosphate groups. This makes the hydrolysis of ATP to ADP energetically favorable
Name three disaccharides
- sucrose
- lactose
- maltose
What is the lytic stage in transduction?
The bacteriophage essentially works to replicate at full speed, making full use of the host cell’s machinery
“releasing hormones” and “stimulating hormones” typically stem from where, respectively?
Releasing hormones (RH) typically come from the hypothalamus (the bridge between the nervous and endocrine system)
Stimulating hormones (SH) typically come from the anterior pituitary
What structure is the most commonly used nitrogen containing reactant at the beginning of the Gabriel synthesis?
Phthalimide
(although other sources of a protected nitrogen can also be used)
What is the acrosome reaction?
the sperm binds to glycoproteins in the zona pellucida, and it releases digestive enzymes (hydrolytic) which create a small tunnel through the zona pellucida (the egg) and allows the sperm nucleus to enter the egg.
What is glycogenin?
The core of a granule of glycogen is the protein glycogenin
this creates the globular shape of glycogen as it moves through the cytoplasm
What is gene flow?
the transfer of genetic variation between populations
How does Lactose affect gene expression in the prokaryotic lac operon?
The lactose isomer, allolactose, binds to the LAC Repressor which then removes it from the operator, allowing transcription to occur
↑ lactose = ↑ gene expression
What are the five types signaling types in biosignaling?
- endocrine
- intracrine
- signals never leave the cell in which they originate and signals remain within the cell
- autocrine
- juxtacrine
- two cells are adjacent to one another and are connected by physical signals
- paracrine
What protecyd yhr 5’ end of a newly synthesized mRNA transcript from degradation within the cytosol?
5’ capping with the 7-methylguanylate cap protects the 5’ end
What is the order of these structures in the heart’s electrical signals
- Atria
- Purkinje fibers
- SA node
- Bundle of His
- AV node
- SA node
- Atria
- AV node
- Bundle of His
- Purkinje fibers
glucagon, insulin, and somatostatin are released by what cells in the pancreas?
In the electron transport chain, the reduction potential of each succeeding complex must _____?
increase
least reduction potential
- complex I
- complex II
- complex III
- complex IV
- oxygen (electrons end up coming to O)
most reduction potential
What is directional selectional?
when the environment is well suited for an extreme phenotype
What is maltose?
A dissacharide (an important byproduct in startch digestion)
glucose + glucose
⍺-1,4 glycosidic bond
What do enzymes do to the activation energy of a reaction?
Lower activation energy (Kinetics)
This enables reactions to occur with less energy available
What is pI (isoelectric point)?
the pH of a solution at which the net charge of a protein becomes zero
what are the 4 phases of cell cycle?
The cell cycle is a four-stage process in which the cell increases in size (gap 1, or G1, stage), copies its DNA (synthesis, or S, stage), prepares to divide (gap 2, or G2, stage), and divides (mitosis, or M, stage)
altogether, this is known as interphase – the stage of the cell cycle that occurs between rounds of cell division (mitosis)
What is the endomembrane system?
The endomembrane system is composed of the different membranes that are suspended in the cytoplasm within a eukaryotic cell.
It includes the membranes of the
nucleus
the endoplasmic reticulum
the Golgi apparatus
lysosomes
endosomes
vesicles
the cell membrane.
It does not include the membranes of mitochondria and/or chloroplasts
What is cooperative binding?
A feature of some proteins comprising more than one subunit is that binding of a ligand to its binding site on one subunit, can increase the affinity of a neighbouring subunit for the same ligand, and hence enhance binding.
This type of allosteric regulation is called cooperative binding
In the male reproductive system, where do sperm mature?
The epididymis
responsible for further maturation of spermatozoa and storage
Does the anterior pituitary release its own hormones? Does the posterior pituitary release its own hormones?
- The anterior pituitary produces hormones
- __i.e. thyroid stimulating hormone (TSH) and luteinizing hormone (LH).
- In contrast, the posterior pituitary does not produce its own hormones
- it only stores and releases hormones that are actually produced in the hypothalamus.
- The two main hormones stored and released by the posterior pituitary are oxytocin and antidiuretic hormone (ADH, aka vasopressin)
What are flippases?
enzymes that move phospholipids from the outer leaflet to the inner leaflet
Which amino acid contains sulfur and can engage in hydrogen bonding?
Cysteine, Cys, C
polar, uncharged
What are scramblases?
enzymes that catalyze the vertical translation of phospholipids from one leaflet of the lipid bilayer to the other
scramblases are bidirectional
What are the products of the pyruvate dehydrogenase complex?
acetyl-CoA
CO2
NADH
(x2 per glucose)
How does acetylation change gene expression?
The acetyl group removes a positive charge from the lysine side of the histone (not the DNA itself), causing its pos/neg interaction with DNA to weaken.
Therefore, it opens up DNA more to be open to transcription factors
increasing/upregulating expression
What are the ribosomes found in eukaryotes?
80S ribsomomes
consisting of 60S and 40S subunits
What step is responsible for the absolute refractory period of an action potential?
Inactivation of sodium channels shuts down sodium influx and is also responsible for the absolute refractory period
What kind of RNA virus needs RNA replicase?
Negative-sense single-stranded RNA viruses
RNA replicase is used to create positive-sense RNA strands that can be translated using host cellular machinery
What is proteolytic processing?
a post-translational modification that involves cleavage of a protein’s primary structure.
This event may generate multiple functional proteins or may simply be used to activate a precursor protein
What is a tropic hormone?
Tropic hormones are hormones that have other endocrine glands as their target
What is the hill coefficient?
it reflects the extent of cooperativity among multiple ligand binding sites
a hill coefficient greater than 1 refelcts positive cooperativity, meaning that binding at one position or active site causes binding to take place more easily at the remaining active sites
What is transduction?
Gene transfer mediated by viruses that infect bacteria (bacteriophages)
increases microbial diversity
What is the zona pellucida?
a layer of glycoproteins coating the secondary oocyte surface
What are gram negative bacteria?
the cell walls of Gram-negative bacteria are characterized by a thin layer of peptidoglycan, surrounded by a lipopolysaccharide outer membrane. They will stain pink instead of deep purple
(peptidoglycan = carbohydrate polymer + amino acid)
what are three eicosanoid signaling molecules?
- prostaglandins
- thromboxanes
- leukotrienes
<em>Eicosanoids are signaling molecules made by the enzymatic or non-enzymatic oxidation of arachidonic acid or other polyunsaturated fatty acids that are, similar to arachidonic acid</em>
A cell’s membrane potential is solely dependent on the relative concentrations of ______?
A cell’s membrane potential is solely dependent on the relative concentrations of intracellular and extracellular ions
Substrate binding curves for cooperative enzymes are what shape on a graph?
sigmoidal S-shape
What are the steps of oogenesis?
The first step in gametogenesis (in both males and females) involves stem cells. In females, primordial germ cells develop into oogonia, which develop into first primary and then secondary oocytes. After arrest in metaphase II, fertilization can occur.
What is distruptive selection?
when two extreme phenotypes are more fit than the intermediate phenotype
In chronological order, what enzymes are involved in glycolysis?
High Profile People Act Too Glamourous, Picture Posing Every Place
What are competitve inhibitors?
an inhibitor that resembles the normal substrate binds to the enzyme, usually at the active site, and prevents the substrate from binding.
What kind of bond connects phosphate groups in ATP?
phosphoanhydride bonds
What is the anatomy of the lac operon?
CAP-Binding Site
Promoter region
Operator (inactive LAC repressor attached)
Lac Z
Lac Y
Lac A
What are endothelial cells?
Endothelial cells form a single cell layer that lines all blood vessels and regulates exchanges between the bloodstream and the surrounding tissues
What is substrate-level phosphorylation?
Substrate-level phosphorylation is a metabolism reaction that results in the production of ATP or GTP by the transfer of a phosphate group from a substrate directly to ADP or GDP.
Transferring from a higher energy (whether phosphate group attached or not) into a lower energy product
What is the shipping side of the golgi apparatus?
the trans-face
What is the difference between the cell wall and the cell membrane?
Cell membrane helps to enclose the cell organelles and cytosol inside a cell
A cell wall is a ridgid, protective layer and it covers the cell membrane.
for plants, <strong>cell walls </strong>are mainly made up of cellulose, while a cell wall in bacteria is made up of peptidoglycan, and for fungi it is made up of chitin
What is the lagging strand in DNA replication?
the strand of new DNA whose direction of synthesis is opposite to the direction of the growing replication fork
(like a back and forth zipper, it is synthesized in back and forth chunks)
What happens in plasmid replication in bacteria?
Every plasmid has its own ‘origin of replication’ – a stretch of DNA that ensures it gets replicated (copied) by the host bacterium.
For this reason, plasmids can copy themselves independently of the bacterial chromosome, so there can be many copies of a plasmid – even hundreds – within one bacterial cell
The humoral immune response results in the production of what large protein structures?
antibodies
antibodies are produced by B-cells and these antibodies bind to specific antigens and mark them for immune destruction
What are 7 neurotransmitters you should be familiar with?
What are multipotent, totipotent, and pluripotent stem cells?
Totipotent stem cells can give rise to all the differentiated cell types in the body + placenta
Pluripotent stem cells can differentiate into several different cell types: can develop into the 3 germ layers known as the endoderm, mesoderm, and ectoderm
Multipotent stem cells can only develop into relatively few cell types
What is the Müllerian duct?
forms the female reproductive tract consisting of the oviducts, uterus, cervix and upper vagina during human development
Where does spermatogenesis occur?
seminiferous tubules are the site of spermatogenesis
What is the three main chacteristic differences between spermatozoa and spermatids?
- spermatozoa have motility
- spermatozoa have tails
- spermatozoa have the acrosomal cap
What are tertiary structures of protein?
They have a single polypeptide chain “backbone” with one or more protein secondary structures
The interactions and bonds of side chains within a particular protein determine its tertiary structure
What is the relationship between enhancers and activators in gene expression?
enhancers are regions located either upstream or downstream (or farther) of their target genes
activators bind to enhancers to upregulate transcription
What is stabilizing selection?
when the intermediate phenotype is better than either of the two extremes
What three steps in gluconeogenesis differ from glycolysis? Think enzymes
- Pyruvate -> Oxaloacetate -> PEP (uses Pyruvate carboxylase then Phosphoenolpyruvate carboxykinase)
- fructose 1,6-bisphosphate → fructose 6-phosphate (uses Fructose 1,6-bisphosphatase)
- glucose 6-phosphate → glucose + Pi (uses Glucose 6-phosphatase)
What two molecules catalyze the first step in strecker synthesis?
KCN and NH4Cl
What is a furanose?
a collective term for saccharides that have a chemical structure that includes a five-membered ring consisting of four carbon atoms and one oxygen atom. (beware, the molecule still contains 6 carbons total)
L-fructose can form what kinds of cyclic rings?
pyranose and furanose
What is quarternary structures of proteins?
Several protein chains or subunits into a closely packed arrangement. Each of the subunits has its own primary, secondary, and tertiary structure.
What is the difference between a cofactor and a coenzyme?
coenzyme is a type of cofactor, but it specifically refers to organic cofactors.
cofactors can be organic or inorganic (i.e. metals)
What is the difference between glycogen and amylopectin?
glycogen is more highly branched (more alpha-1,6 bonds)
What 2 main hormones are released by the posterior pituitary?
- Vasopressin, also referred to as antidiuretic hormone (ADH)
- Oxytocin
Where is the hormone thymosin secreted from?
The thymus
The thymus secretes thymosin, which promotes the development of T-cells, a key part of the immune system
What are primary structures of proteins?
linear sequence of amino acids that forms the backbone of a functional protein
In the parasympathetic nervous system the preganglion is long or short?
Parasympathetic preganglionic axons tend to be relatively long, (while postganglionic axons are relatively short)
What is the relationship of lactose and glucose to the prokaryotic lac operon gene expression?
What are five hormones that the anterior pituitary are responible for secreting?
What is the R and T state of hemoglobin mean?
Whenever oxygen is bound, hemoglobin exists in the R (relaxed) state, and oxygen affinity is high.
In contrast, the T (taut) state is marked by low oxygen affinity.
How do enhancers + activators upregulate gene expression in eukaryotes?
activators bind to the enhancer region and then help twist the DNA into a hairpin loop back onto itself to bring the enhancer region closer to gene sequence in order to facilitate the initiation of transcription
The umbilical vein carries what kind of blood? Is this to or away from the fetus?
The umbilical vein takes oxygenated blood from the placenta to the fetus’s heart
What primarily makes up viral envelopes?
viral envelopes are primarily made up of phospholipids (as in the cell membrane)
What is convergent evolution?
organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches
What connects cardiac muscle cells?
Cardiac muscle consists of individual cells connected by intercalated discs to work as a single functional organ
What is peptidoglycan
The main component of bacterial cell walls (not the cell membrane)
consists of carbohydrate (polysacchrides) that is modified with amino acids for stability
What is the precentral gyrus? (brain)
The precentral gyrus, which contains the primary motor cortex, is the original source of motor signals (voluntary motor control)
What is the equation for resistance?
What are platelets derived from?
Platelets are cellular fragments derived from megakaryocytes
Describe the negative feedback loop in prokaryotic trp Operon gene expression
The trp operon is defaulted in the “on” position (tryptophan absent)
this operon then codes for the synthesis of tryptophan
The repressor then binds to tryptophan which then binds to the operator and inhibits gene expression (“off” position)
What is the main inhibitory hormone in the digestive system?
Somatostatin
Where do anomeric carbons derive from?
Anomeric carbons are derived from the only carbon with a double bond to oxygen (sp2 carbon)
this is always the carbonyl carbon in carbohydrates
What are the broad functions of the following regions of the cerebrum:
The frontal lobe is responsible for most higher order functions that we associate with humans, such as cognition. It also contains the primary motor cortex, where voluntary muscle impulses originate.
The parietal lobe contains the primary somatosensory cortex and processes most somatosensation (touch).
The temporal lobe processes language, as well as most sound input in general, and plays some role in memory formation.
The occipital lobe is most notable as the termination point of the visual pathway (which is why trauma to the back of the head can induce visual damage)
Explain why DNA is replicated via a semiconservative mechanism?
parent dsDNA denatures so that each strand is used as a template to form new DNA. As a result, the two dsDNA products from the first replication each contain one original DNA strand and one new strand
What is spermatogenesis
Spermatogenesis is the process by which haploid spermatozoa develop from germ cells in the seminiferous tubules of the testis
A western blot measures the levels of ____
Proteins
thickness of band –> expression levels
location of band –> size of protein
Where is epinephrine and norepinephrine (catecholamines) released from?
Adrenal medulla
(cortisol is released by the adrenal cortex)
Where is the thalamus located?
located in the forebrain, specifically in the diencephalon
What is transformation (bacteria)?
Bacterium absorbs DNA from the environment
Hydroxyl groups that are shown on the ____ side of a Fischer projection will end up displayed below the ring in the Haworth projection of the sugar
Right
How do bile salts break down fat?
Bile salts are amphipathic molecules that associate with lipids in the aqueous environment of the duodenum
Bile salts generate more lipid surface area through a process called emulsification. This makes fat globules more accessible to water-soluble lipases, which chemically digest lipids
What is normality?
Normality (N) is defined as the number of mole equivalents per liter of solution: normality = number of mole equivalents/1 L of solution.
Like molarity, normality relates the amount of solute to the total volume of solution; however, normality is specifically used for acids and bases.
How are glycosidic bonds formed and broken?
they are strong covalent bonds formed through enzymatic catalysis_/dehydration (condensation)_
and broken through acid-catalyzed hydrolysis reactions
these reactions are reversible
always formed with the anomeric carbon (C1) on at least one of the sugars
What are the four major steps of neurulation?
- cells from the mesoderm form the notochord which then induces:
- cells from the ectoderm form the neural plate
- the neural plate invaginates to form a central neural groove
- neural crest cells migrate to form the peripheral nervous system
occurs within the first three weeks of development
What 4 substrates act as starting materials in gluconeogenesis?
- amino acids (except leucine and lysine)
- glycerol (from fatty acid breakdown)
- lactate
- pyruvate
What are F+/F- bacteria?
The F sex factor; also called F-plasmid
allows genes to be transferred from one bacterium carrying the factor to another bacterium lacking the factor by conjugation.
Which enzyme catalyzes the rate-limiting step of glycolysis?
Phosphofructokinase
What are the 4 enzymes used exlusively in gluconeogensis compared to glycolysis?
Gluconeogenesis must overcome the three irreversible glycolytic steps. The enzymes used to achieve this are
glucose 6-phosphatase,
fructose 1,6-bisphosphatase,
PEP carboxykinase
and pyruvate carboxylase.
what stage in meiosis does recombination occur?
Prophase I
Where does the restriction point (the point at which a cell is committed to undergoing mitosis) occur in cellular divison?
G1
Where does protein translation occur in the cell?
Translation takes place on ribosomes in the cell cytoplasm,
This is where mRNA is read and translated into the string of amino acid chains that make up the synthesized protein
What is the pathway for protein modification in a eukaryotic cell?
in the transport of proteins that need to be modified, the usual process to produce these proteins follows these steps:
Cytoplasm->
Endoplasmic Reticulum->
Golgi Apparatus->
Cell Membrane
Which type of cell contains a Golgi apparatus?
eukarya
Cytochrome C transports how many electrons during ETC (i.e oxidative phosphorylation)?
1 electron
Cytochrome c is a heme protein that cycles between a ferrous (Fe+2) and ferric (Fe+3) state during oxidative phosphorylation.
Therefore, only a single electron is transferred in the process
Where does glycolysis take place?
Glycolysis takes place in the cytoplasm
What makes up a fatty acid?
A fatty acid is comprised of a long hydrocarbon tail and a head consisting of –CO2–, a carboxyl group
Do archea and bacteria cells have organelles?
No
Archaea and bacterial cells lack organelles or other internal membrane-bound structures.
Therefore, unlike eukaryotes, archaea and bacteria do not have a nucleus separating their genetic material from the rest of the cell
What cell stage of spermatogenesis is the first one to be haploid?
Secondary spermatocyte
What cofactor is essential for PCR to proceed?
Magnesium Chloride
MgCl2 (Magnesium chloride) is an essential ingredient of the PCR master mix. Acting as a cofactor, it enhances the enzymatic activity of DNA polymerase, thereby boosting DNA amplification. Cofactors are non-protein ions or molecules that help enzymes perform their functions.
What form the sctructural support for the nuclear membrane?
intermediate filaments
Intermediate filaments form an elaborate network in the cytoplasm of most cells, extending from a ring surrounding the nucleus to the plasma membrane
lamins are comprised of intermediate filaments that form the structural support for the nuclear membrane
What hormone is responsible for ovulation?
luteinizing hormone is the hormone responsible for triggering ovulation
What are chaperone proteins?
proteins that assist the conformational folding or unfolding of large proteins or macromolecular protein complexes
inhibits the formation of nonfunctional protein aggregates
What are clathrin proteins?
Clathrin functions in formation of vesicles for intracellar traffickin
plays a major role in the formation of coated vesicles
what are adhesion proteins?
Adhesion proteins act in binding with other cells or with the extracellular matrix
What direction is DNA synthesized in?
DNA is always synthesized in the 5’-to-3’ direction,
meaning that nucleotides are added only to the 3’ end of the growing strand
What direction is RNA synthesized in?
All mRNAs are synthesized in the 5´ to 3´ direction, and polypeptide chains are synthesized from the amino (N) to the carboxy terminus (C)
It synthesizes the RNA strand in the 5’ to 3’ direction, while reading the template DNA strand in the 3’ to 5’ direction.
In glycolysis, how many NAD+ molecules are reduced?
2 NAD+ molecules are reduced to NADH
What are the products from ONE round of the Krebs Cycle?
- 1 GTP
- 3 NADH
- 1 FADH_{2}2start subscript, 2, end subscript
- 2 CO_{2}2start subscript, 2, end subscript
- Regenerated oxaloacetate
What is chemiosmosis?
Chemiosmosis involves the pumping of protons through special channels in the membranes of mitochondria from the inner to the outer compartment
chemiosmosis is the movement of H+ ions DOWN its gradient in the final step of the ETC. it is distinct from the rest of the ETC because up until this point, the complexes have been pumping Hydrogens out of the matrix and now in the final step - Chemiosmosis - they get to come back into the matrix through ATP synthase
What structure in the kidney does water reabsoption take place?
The collecting duct is the final structure in which water reabsorption occurs, which concentrates filtrate
What are the three segments of the collecting duct in the kidney called, and what is their position relative to each other?
- cortical collecting duct (in cortex of kidney – most amount of water, least concentrated urine)
- outer medullary collecting duct (in outer medulla)
- iner medullary collecting duct (in inner medulla – least amount of water, most concentrated urine)
At rest, what ions mostly fill the axon of a neuron?
At rest, there are relatively more sodium ions outside the neuron and more potassium ions inside that neuron.
What is the purpose of the Na+K+ ATPase pump?
The restoration and maintenance of the resting potential relies on Na+/K+ ATPase.
This is achieved by moving three Na+ out of the cell for every two K+ ions that are brought into the cell.
What are 3 functions of microtubules?
In a cell, microtubules play an important structural role, helping the cell resist compression forces
microtubules have directionality, meaning that they have two ends that are structurally different from one another – they provide tracks for motor proteins called kinesins (anterograde – center to periphery) and dyneins (retrograde – periphery to center), which transport vesicles and other cargoes around the interior of the cell
During cell division, microtubules assemble into a structure called the spindle, which pulls the chromosomes apart.
Microtubules are key components for what 3 eukaryotic cell structures?
flagella (motility/cell movement)
cilia (motility/cell movement)
centrosome (regulates cell motility, adhesion and polarity in interphase, and facilitates the organization of the spindle poles during mitosis)
What are the 5 functions of microfilaments (also known as actin filaments)
- serve as tracks for the movement of a motor protein called myosin
- actin is involved in many cellular events requiring motion.
- serve as highways inside the cell for the transport of cargoes, including protein-containing vesicles and even organelles
- These cargoes are carried by individual myosin motors, which “walk” along actin filament bundles
- cell motility (movement), such as the crawling of a white blood cell in your immune system.
- actin filaments play key structural roles in the cell
- a network of actin filaments is found in the region of cytoplasm at the very edge of the cell.
- This network, which is linked to the plasma membrane by special connector proteins, gives the cell shape and structure
how does the initial filtration step in the glomerulus of the mammalian kidney occur?
passive flow due to a pressure difference
What is an obligate parasite?
A parasitic organism that requires the host organism to complete its life cycle is known as an obligate parasite.
How are nucleotides linked?
Nucleotides are linked to one another by phosphodiester bonds between the sugar base of one nucleotide and the phosphate group of the adjacent nucleotide in a way that the 5′ end bears a phosphate, and the 3′ end a hydroxyl group
How many hydrogen bonds exist between C and G on double helix DNA?
3 hydrogen bonds
What happens when Na+ enters a neuron?
As sodium enters the cytoplasm of the cell, the membrane potential will increase and the cell will depolarize
What portion of the cell is responsible for protein modification?
The endomembrane system is the portion of the cells that is in charge of modifying proteins that will be secreted
What are major functions of the liver?
- detoxification of poisons
- the production of bile
- facilitates fat absorption in the small intestine by breaking large fat droplets into smaller ones
- produces the protein albumin, which helps transport various hormones in our bloodstream
- storage of vitamins and minerals
- production of cholestoral
- glycogen storage
Where do microtubules originate from?
microtubules are cellular structures that originate from centrosomes
What differentiates cardiac muscle from skeletal muscle?
One of the hallmarks of cardiac muscle tissue is an action potential with a “plateau” in its depolarization. Specifically, repolarization is delayed due to the action of slow-to-open voltage gated Ca2+ channels. This maintains the regular beat of the heart. Skeletal muscle, on the other hand, lacks such a plateau, and the opening of potassium channels is able to rapidly repolarize the cell.
are eukaryotes carry monocistronic or polycistronic mRNA?
monocistronic
monocistronic mRNA contains genetic information of a single protein. They produce separate mRNA transcripts for different genes
while the polycistronic mRNA carries the genetic information of several genes which are translated into several proteins.
What is the purpose of the cori cycle?
Cori cycle prevents lactic acidosis (excessive accumulation of lactate) in muscle under anaerobic conditions.
This cycle is also important for production of energy molecule (ATP) during muscle activity, as muscles get deprived of energy due to insufficient glucose
what is gene imprinting?
Genomic imprinting is the process by which only one copy of a gene in an individual (either from their mother or their father) is expressed, while the other copy is suppressed
What structure in the kidney prevents the entry of large molecules, such as proteins, into the filtrate?
Glomerulus
What is Henry’s constant KH?
Henry’s Law is a law stating that the mass of a dissolved gas in a given volume of solvent at equilibrium is proportional to the partial pressure of the gas.
What are the three binding sites for tRNA during translation?
During protein translation, aminoacyl transferase functions to transfer the tRNA originally bound at the A (amino acid) site to the P (peptide) site and later to the E (exit) site of the ribosome
What is gel filtration?
Gel filtration is also known as size-exclusion chromatography or molecular-sieve chromatography
a chromatographic method in which molecules in solution are separated by their size, and in some cases molecular weight. It is usually applied to large molecules or macromolecular complexes such as proteins and industrial polymers
