Flashcards in MCAT Bio Biochem Deck (182)
What are the two main componenets of the viral envelope.
Viral envelopes consist of phospholipids and glycoproteins that contribute to recognition and interaction with other cell receptors.
Name each type of inhibition and what they all affect?
Competitive inhibition--> Increases Km and Vmax unchanged.
Noncompetitive inhibition--> Vmax is decreased while Km is unchanged.
Uncompetitive inhibition--> Vmax and Km both decrease.
What is the term used to describe "catalytic efficiency"?
What is the order of scope covered from largest to smallest with Coenzymes, Prosthetic groups, and Cofactors?
Where are action potentials summated?
Action potentials begin in the axon hillock before they move down the axon.
What is hyperpolarization?
Hyperpolarization happens when the membrane potentail changes to a negative membrane potential due to the loss of potassium ions in the cell.
Which neurotransmitter would cause muscle flacidity? 1) Acetylcholine 2) Glutamine 3) Epinephrine 4) GABA
Muscle flacidity is caused by a lack of acetylcholine released by somatic cells that causes muscles to not contract.
What muscles would be expected to be forcefully contracting if a patient is struggling to breathe?
Forceful exhalation is defined as a contraction of the internal intercostal muscles to force air out, which is abnormal.
What is pulmonary surfactant and how does it affect respiration?
Pulmonary surfacant in involved in the reduction of aveolar surface tension. Decreased amounts of surfactant can lead to less area for gas exchange causing difficulty breathing.
What is ADH, Aldosterone, and ANP? What are their functions?
Vasopressin (ADH) is involved with water retention. So, a vasopressin receptor antagonist will cause the receptors to NOT retatain water causing large amounts of urine to be excreted. Aldosterone and ANP are also involved in either secretion of water/sodium or the retention of such. All are invloved in kidney function and urine secretion.
How do you know the change in pressure between the Glomerular Capillaries and the Bowman Space? Hint: It is positive/negative depending on the direction of flow.
Pressure going into the Bowman Space (from the Glomerular) is positive and flowing into the Glomerular Capillaries is negative.
If the anterior pituitary malfunctioned, what would be the resulting affect on the Thyroid?
The anterior pituitary gland creates a hormone called TSH (Thyroid stimulating horome) that stimulates the Thyroid to create T3 and T4 hormones
What is the function of the Pineal gland? What Bodily cycle does it tie into?
The Pineal gland secretes Melatonin (Melatonin production is stimulated by darkness and inhibited by light).
What would happen to the body if the concentration of aldosterone increased? (hint: It affects Sodium, Water, and Potassium.)
As Aldosterone concentration increases, water and salt retention will also increase, while potassium will be secreted due to stimulation of the distal ducts on the kidney nephron.
What are the affects of LH on both men and women?
Increase in LH will stimulate the follicles on the ovary to undergo ovulation. However, for males, LH will bind to receptors to stimulate testosterone synthesis.
Where are phospholipids created?
Phospholipids are synthesized on th surface of the smooth ER then packaged into vesicles and sent to the membrane.
What are dyeins and what is their function?
dyneins--> are motor proteins that are structurally similar to kinesins, but carry cargo toward the minus end of the mircotubule, which is usually oriented toward the center of the cell. There are two other types that are found in a smaller scale that either help with cellular transport or function of filia or flagella.
What are Kinesins and what is their function?
Kinesins--> are motor proteins that use ATP to power movement across microtubules and usually go towards the periphery (outside of the cell). They are also made up of four distinct subunits.
What are Myosins and what is their function?
Myosins--> similar to kinesins/dyneins (need ATP) but are not involved in transport. They play a role in actin-based muscular contraction in muscle, as well as a winde rande of motility processes (including actin contraction in cleavage furrow of cell seperation). Use ATP to carry out power stroke.
What is the fuction of actin microfilaments?
Actin Microfilaments (smallest of the skeleton)--> play a role in motility, cell cleavage, endocytosis/exocytosis, and muscle contraction.
What is the function of Intermediate filaments?
Intermediate filaments (the middle sized in the cytoskeleton)--> provide stuctural support and other functions; major example = Keratin (findernails, etc.).
What is the function of Mircotubules?
Microtubules (largest in cytoskeleton)--> Hollow cylinders composed of poolymeric tubulin dimers (alpha and beta). Contribute to chormosome movement during division and intracellular division.
What are the three types of junctions and their functions?
Anchoring junctions--> involve cadherins; help keep cell/tissue in place. Gap junctions--> formed by connexin proteins, connects cells so that diffusion/communication can take place. Tight junctions--> invlove several types of proteins, are found in epithelial cells, and prevent solutes from being able to move freely between tissues (i.e. blood-brain barrier).
In oogenesis, when does the primary occytes turn into the secondary occyte (it's either before birth or at puberty)? When are they diploid and haploid?
When women are born, they are born with primary oocytes arrested in Meiosis I. When puberty occurs, those primary occytes complete meisis I and become secondary occytes that are haploid (while primary occytes are diploid).
What hormone is released when the egg attaches to the uterine lining and what mechanism does it stimulate?
Directly after the egg implants in the uterine lining, it releases cHG, that mimics LH, to maintain the Corpus Luteum, thus maintaining estrogen and progesterone levels to signal to the body that pregnancy is occuring.
What are Osteoblasts/Osteoclasts and their function?
Osteoblasts -->use hydroxyapatite to create the bone matrix. Osteoclast--> Break down the bone matrix to inject calcium and phospate into serum levels if they're low.
What is the difference between ligaments and tendons?
Ligaments: Are used to connect bone to bone. Tendons are used to connect muscle to bone.
How would you go about finding what estradiol looks like when given four different steriods to choose from?
Estradiol (a steriod and a form of estrogen) is going to have the common 4-ring that steriods normally have. Also, the -diol refers to OH (hydroxy) groups attached to the steriod. Di means two. So, it should be relatively easy to reason through.
What is the difference between multipotent, pluripotent, and totipotent stem cells?
Multipotent stem cells--> in various types of tissue and can develop onto various forms, unlike other types. Pluripotent stem cells--> are similar to multipotent cells but are NOT found in adults.
Totipotent stem cells--> Can give rise to embryos or placental tissue but cannot form anything else and are NOT found in adults.