Biology/BioChem Review Flashcards
Can a virus ever undergo meiosis?
No, they lack the “complex cellular machinery”.
Natural killer cells are part of which immune system?
Innate
NK and Cytolytic T cells do what?
Destruction of one’s own cells that are either cancerous or virus infected
Innate immune system
cells and proteins that are always present and ready to mobilize and fight microbes at the site of infection.
1) physical epithelial barriers, 2) phagocytic leukocytes, 3) dendritic cells, 4) a special type of lymphocyte called a natural killer (NK) cell, and 5) circulating plasma proteins. 0-12 hr timeline
Adaptive immune system
called into action against pathogens that are able to evade or overcome innate immune defenses.
humoral immunity, mediated by antibodies produced by B lymphocytes
cell-mediated immunity, mediated by T lymphocytes.
Leukocytes are:
White blood cells. Types of leukocytes are: lymphocytes, neutrophils, basophils, eosinophils, monocytes, and macrophages
Start codon:
AUG
3 stop codons:
UAG, UAA, and UGA.
Primary immune response:
occurs when an antigen comes in contact to the immune system for the first time. During this time the immune system has to learn to recognize antigen and how to make antibody against it and eventually produce memory lymphocytes. (B cells)
Secondary Immune response:
occurs when the second time (3rd, 4th, etc.) the person is exposed to the same antigen. At this point immunological memory has been established and the immune system can start making antibodies immediately.
Smooth ER:
Lipid synthesis/modification (but NOT lipid metabolism; many students get this confused. Lipids are made at the ER, but metabolized in the mitochondria).
Tubulin:
a globular protein that polymerizes to form microtubules.
Cytoskeleton:
scaffolding-like network of microfilaments, microtubules, and intermediate filaments that provides structure to the cell and creates a highway of sorts for intracellular transport.
Actin:
a protein monomer that polymerizes to form microfilaments. Also forms thin filament portion of sarcomere.
Microtubules:
Make up cilia and flagella. (9+2 arrangement)
Adherens Junctions:
are found in epithelium and between cardiac muscle cells.
Desmosomes:
occur in tissues subject to shear stress such as the epidermis.
Endocrine signaling:
Hormones are manufactured and secreted by cells in the endocrine glands, travel in the bloodstream, then bind to receptors either on the cell surface (in the case of water-soluble hormones) or inside the cell (in the case of lipid-soluble hormones).
Intracellular receptor:
Lipid-soluble hormones (e.g., steroids) do not require a plasma membrane surface receptor. They dissolve through the membrane and bind targets in the cytosol which often move to nucleus to act.
Paracrine signaling: (Pair…acrine)
Signal molecules secreted by one cell bind to receptors on other cells in the local area. Neurotransmitters acting in the synaptic gap are an example of a paracrine response.
Autocrine signaling: (auto: self)
Signal molecules secreted by a cell bind to receptors on that same cell.
Intracrine signaling: (intra: within)
Signal molecules (usually steroids) bind to receptors inside the same cell that producedthem, without ever being secreted outside of the cell.
Juxtacrine signaling:
Signaling requires direct contact between two cells.
Histones:
the proteins around which the DNA helix is wrapped during the first step of DNA condensation to form a chromosome
Nucleosome:
a set of eight histone proteins in a cube
shape with DNA coiled around it much like thread wound around a spool.
Centromere:
the region of the chromosome that joins the two sister chromatids
Kinetochore:
a specialized group of proteins to which the
spindle fibers attach directly during mitosis/meiosis.
IPMATC:
Interphase: uncoiled chromosomes Prophase: Cell membrane disolved Metaphase: Chromosomes line up Anaphase: Chromosomes are separated and begin migration Telophase: Nuclear membranes reforming.
Mitosis:
Two (2) genetically identical, diploid daughter cells
Meiosis:
Four (4) genetically distinct, haploid daughter cells
When does crossing over occur?
During Prophase of Meiosis I
What makes up a nucleotide? 3 components
Base, Sugar, triphosphate
What are purines and what are pyrimidines?
Adenine and Guanine are Purines.
Thymine and Cytosine are Pyrimidines, also Uracil is a pyrimidine.
Origin of replication:
the location on the chromosome where replication begins. For human chromosomes there are multiple origins.
Restriction endonucleases:
enzymes that cut DNA at specific pre-determined sequences.
Sticky ends:
are so named because the endonuclease cuts the DNA in a staggered fashion that leaves one side of the helix longer than the other
Recognition Sequence:
The specific base sequence recognized by the endonuclease
Vector:
a segment of DNA used to transfer a desired sequence into another cell.
Phage:
an abbreviated name for a bacteriophage (a virus that infects bacteria)
Gel electrophoresis:
mixture of molecules (usually nucleotide segments or proteins) is loaded onto a plate covered
with an agarose gel. A charged field is created across the gel. Because nucleotides are negatively
charged (due to the phosphate groups) they will be pulled through the gel toward the positive
side of the field, which is called the anode
Southern blot: PCR
Used to verify the presence/absence of a specific DNA sequence. It will also indicate the relative size of restriction fragments.
Northern BLot:
Nearly identical to a Southern Blot; used on RNA instead of DNA.
Western blot:
Same basic procedure and concepts as Northern and Southern blots; used on proteins segments instead of nucleotide segments. The probes used are radio-labeled antibodies rather than nucleotide sequences.
Eastern blot:
Similar to a Western blot, but used to verify post-translational modification. The probes used bind to lipids, carbohydrates and phosphates (i.e., the most common posttranslational modifications).
Ribosomal rRNA
is the polymer of which ribosomes are constructed. Remind students that ribosomes are assembled in the nucleolus. Ribosomes are a non-protein entity that act as enzymes in the polymerization of proteins, and are an example of a non-protein enzyme.
Transfer tRNA
the molecule that bridges the gap between mature mRNA and the assembled protein
Messenger mRNA
the complementary RNA strand copied from the DNA template strand. Has pre-mRNA which still contains non coding segments, and once removed has mature mRNA
Alternative Splicing:
refers to the fact that after introns are removed from the mRNA transcript, the exons can be assembled in any of a number of different orders—each variation resulting in a different protein.
Lactase:
the enzyme that digests lactose in bacteria.
post translational modification:
Occurs at the endoplasmic reticulum and the Golgi apparatus; usually includes addition of polysaccharides, lipids, or phosphates.
Nonsense mutation:
a mutation that changes a normal codon into a premature stop codon.
Frameshift mutation:
any mutation that changes the reading frame. This would be any insertion or deletion that does not occur in multiples of three.
Heritability in germ and somatic cells:
the next generation will ONLY receive the genetic information found in the sperm or egg cell they receive from each respective parent. Mutations to any or all somatic cells will not be incorporated into the offspring.
Incomplete penetrance:
when various individuals all have identical genotypes and yet some have the disease phenotype and others do not
Polygenic:
when many genes contribute to one phenotypic trait.
Pleiotropy:
describes the situation in which one single gene contributes to multiple phenotypic traits.
Mosaicism:
different cells within the same individual contain non-identical genotypes
Epigenetic:
refers to any heritable phenotype resulting from any process other than a change in the DNA sequence itself. epi like outside
What could be the cause of an unexpected ratio of genetic inheritance?
Linkage
Polymorphism:
random variations in genetic sequence among individuals. If beneficial, would stay in next generations.
Adaptive radiation:
the rapid formation of a variety of species from one ancestral species—usually characterized by a strong environment-species connection
In order for natural selection to occur: 2 things
Fitness advantage from polymorphism, this results in more offspring produced from this individual
Convergent evolution:
results when two species arrive at a point where they have similar functional forms, but they have developed those similar forms via different evolutionary pathways. EX: bat and bird
Divergent evolution:
the process by which species develop different forms AND thereby form new species, all radiating from that common ancestor. is an example of adaptive radiation
Hardy Weinberg equilibrium:
p2 + 2pq + q2 = 1
p+q=1
Kingdom Phylum Class Order Family Genus Species: of humans
King Phillip Came Over From Great Spain:
K: Animalia P: Chordata C: Mammalia O: Primates F: Hominidae G: Homo S: Homo Sapiens
Autotrophs:
are capable of fixing CO2 and can therefore use CO2 as their carbon source for synthesizing organic molecules.
Heterotrophs:
cannot fix CO2 and therefore must ingest organic molecules such as carbohydrates as their carbon source
Fungi:
grow via long, intertwining branches called hyphae. Hyphae are haploid and a mass of
hyphae is called a mycelium.
Commensalism:
symbiosis in which one participant benefits and the other participant’s experience is neutral— neither beneficial nor harmful
Lichen
Symbiosis between fungi and algae.
Bacteriophages
Virus that infect bacteria. Have a head, a tail, tail fibers, can contain dna or rna
Envelopes viruses
Ex:cold virus or HIV, small spherical membranes surrounding a protein capsid and nucleic acid. Retroviruses always contain RNA and reverse transcriptase enzyme
Glomerulus:
a fenestrated capillary bed that strains the blood—allowing fluids, ions, and molecules the approximate size of glucose or smaller to pass through into Bowman’s capsule.
Proximal tubule:
Sodium is reabsorbed via active trasport,and glucose is reabsorbed via secondary active transport through a symporter. because water and solutes are reabsorbed in the same ratio, the filtrate remains isotonic
Descending loop of henle:
This section of the nephron is impermeable to salts, but very permeable to water.
Water therefore flows out of the filtrate and into the medulla, concentrating the urine.
Ascending loop of henle:
This portion of the loop is impermeable to water and actively transports ions out of the filtrate and
into the medulla.
Distal tubule:
regulates calcium, sodium and hydrogen concentrations. Recall that aldosterone stimulates increased sodium reabsorption at the DCT and the collecting duct
Aldosterone:
also causes reabsorption of Na+ out of the collecting duct via the insertion of Na+ channels, K+
channels, and Na+/K+ ATPases in the cells that line the collecting duct. The net effect = water
retention and increased blood pressure.
ADH:
acts on the collecting duct, making it permeable to water
The net effect = water retention and increased blood
pressure.
Path of air in respiration:
Mouth/nose -> pharynx -> larynx ->trachea ->bronchi ->bronchioles -> alveoli.
Tidal Volume:
the volume of air that enters and exits the lungs during an average, unforced respiration
inspiratory reserve volume (IRV) and
an expiratory reserve volume (ERV).
This is the volume of additional air that can be exhaled or inhaled after a normal, unforced expiration or inhalation
Residual volume:
amount of air left in the lungs after a forced, maximal exhalation
Vital capacity:
the total volume of air the lungs can hold at maximum inflation, minus the residual volume.
Hemoglobin:
4 subunits, each with one heme, each heme holds one O2 molecule. 1 Hemoglobin=8 O molecules
Equation for CO2 dissolving in blood:
CO2 + H2O = HCO3- + H+
Sympathetic NS activity:
increases heart rate and blood pressure. “Fight or Flight.” Cell bodies located far from the effectors. Neurotransmitters-> acetylcholine at the ganglia, norepinephrine at the effector.
Parasympathetic NS activity:
decreases heart rate and blood pressure.“Rest and Digest.” Cell bodies located very close to, or inside, the
effector. Neurotransmitters: acetylcholine only, at both the ganglia and the effector.
Platelets:
Tiny membrane-bound drops of cytoplasm. They are sticky when exposed to injured epithelium and non-sticky to healthy epithelium. If they encounter injured epithelium, they release chemicals that activate other platelets and clotting factors.
Hematopoesis:
All blood cells develop from stem cells (undifferentiated cells) in the bone marrow;
Function of the Lymphatic system:
Gather excess interstitial fluid and return it to the blood; remove from the interstitial spaces proteins and other molecules too big to be taken up by the capillaries;
monitor the blood and lymph for infection
Where do lymphatic vessels drain?
into two main vessels, the right lymphatic duct and the thoracic duct, which both dump back into the blood stream by merging with large veins in the lower portion of the neck.
4 Characteristics of Neurons:
1) Are frozen in G0 phase (unable to divide)
2) Depend entirely on glucose for energy
3) Don’t require insulin for glucose uptake
4) Have very low glycogen; oxygen storage capability and thus require high perfusion (blood flow)
Sodium/potassium pump:
An ATP pump that actively transports 3 Na+ ions out of the cell and 2 K+ ions into the cell per cycle.
Voltage Gated Sodium Channels:
In their “open” state, they allow the rapid flow of sodium back into the cell.
Depolarization:
The opening of the voltage gated sodium channels causes a sudden spike in the membrane potential, from -70 mV to somewhere around +40 mV
Where is the threshold potential?
around -55mV
Where are electrical synapses found?
the retina, smooth muscle, cardiac muscle, and the CNS.
Acetylcholinesterase:
Specialized enzymes in the synaptic cleft must break down the neurotransmitter to interrupt its action. If this didn’t occur, the NT’s (often acetylcholine) would continue to signal.
Schwann cells and oligodendrocytes:
Schwann cells: PNS wrap neuron
Oligodendrocytes: CNS wrap neurons
Ependymal cells:
classified as epithelial and neural: cells lining the
cerebrospinal fluid cavities for support.
Sensory neurons: (afferent)
Receive sensory signals from sensory cells.
Motor neurons: (efferent)
Carry signals to a muscle or gland to respond to the stimulus. Synapses with “receptor” and “effector”
Interneurons:
Connect afferent and efferent neurons. They also transfer and process signals. The brain and 90% of all other neurons are interneurons.
Endocrine system:
release hormones into the internal fluids of the body (e.g., blood, lymph, etc.).
Peptides:
Water soluble
Anterior pituitary hormones: (are released by hormones coming from hypothalamus)
FSH, LH, ACTH, hGH, TSH and Prolactin
Posterior pituitary hormones: (are released by hormones coming from hypothalamus)
ADH and Oxytocin
What hormone does the parathyroid release?
PTH- Parathyroid hormone
What hormone does the pancreas release?
Glucagon; Insulin
Thyroid:
Calcitonin
Embryo/Placenta:
hCG (Human Chorionic Gonadotropin)
Steroids:
All are lipid soluble and are cholesterol derivatives.
Tyrosines:
Lipid soluble (which require a vesicle for transport)
Lipid soluble hormones: (do not require membrane receptor, can diffuse freely)
(which require a vesicle for transport) almost exclusively act by binding to a receptor on or inside the nucleus and influencing transcription; peptide hormones, by contrast, act at a variety of cell locations.
What is the 1 major important rule about hormones?
Hormones always act to return the system to homeostatic, or “normal,” conditions. They never cause a drift away from normal.
INSULIN:
When high blood glucose levels are detected, the body tells the pancreas to produce insulin which causes the cells to uptake glucose from the blood, decreasing the levels.
GLUCAGON:
When low blood glucose levels are detected, the body tells the pancreas to produce glucagon which stimulates the liver to break down glycogen to release glucose into the blood, raising the levels.
Increase CO2=low pH (acidic)
Decrease CO2=high pH (basic)
Describe how this affects BP:
If BP is increased, velocity of blood increases, allowing less time for CO2 to be dumped in blood, causing more basic blood.
What specific type of cell does not require insulin to uptake glucose?
NEURONS
What neurons are in the CNS?
Interneurons only
What neurons are in the PNS?
Somatic: voluntary, skeletal muscle and has sens and mot
Autonomic: involuntary, innervates cardiac muscle, smooth muscle, and glands. Has sens and mot
Sensory:
Motor:
Sympathetic:
Parasympathetic:
4 different substituents of an amino acid?
contains four different substituents, an –R group, a hydrogen, a carboxylic acid, and an amine. All can be synthesized from glyceraldehyde
Are most amino acids found in human body D or L?
L, oriented with COOH at top, -R on bottom, amine group will be on left in fisher projection
-R groups of amino acids determine what?
CHEMISTRY, and folding of proteins and how they will interact
How will a protein fold?
Hydrophobic –R groups fold INTO the protein core
(hydrophobic environment), and hydrophilic –R groups are more common on the surface of the protein (hydrophilic environment).
Zwitterion
A dipolar version of an amino acid wherein
positively and negatively charged functional
groups cancel one another out, resulting in a
neutral ion
Salt bridges:
Formed when acidic and basic –R groups undergo a neutralization reaction resulting in a salt.
What kind of resonance is demonstrated in a peptide bond?
BOTH the C=O bond and the C-N bond in a
peptide bond have DOUBLE BOND character.
What molecules cleave proteins on carboxylic acid side of amino acids?
- Trypsin = arginine, lysine
* Chymotrypsin = phenylalanine, tryptophan, tyrosine
How far apart are the hydrogen bonds in an alpha helix?
4 amino acids apart, including AA’s participating in bonds. R groups are directed exactly away from the alpha helix cylinder
Beta sheets:
EX: keratin, fibroin
H bonding between carbonyl oxygens and NH hydrogens.
ALL residues involved in hydrogen bonding!
Proline usually and end of row to induce 180 deg turn
The six types of interactions in teritary protein structures?
Hydrogen bonding, disulfide bonds, hydrophobic/hydrophilic interactions, Ionic interactions, van der wals forces, proline turns .
