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MCAT
Hormones, Nervous system, problem areas!
107
Biology
Undergraduate 4
03/16/2007

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Term
What is FHS, where is its source, and what is the action
Definition
Follicle stimulating hormone; anterior pituitary; stimulates follicle maturation, and spermatogenesis
Term
What is adrenocoritcotropic; source and action?
Definition
Anterior pituitary; stimulates adrenal cortex to make and secrete glucocorticoids
Term
What is TSH/ source/function?
Definition
Thyroid=simulating hormone; anterior pituitary, stimulates thryoid to produce thyroid hormones
Term
Prolactin?
Definition
Anterior pituitary; stimulates milk production and secretion
Term
Endorphins
Definition
Anterior Pituitary; inhibit perception of pain to the brain
Term
Growth hormone
Definition
anterior pituitary; stimulates bone and muscle growth/lipolysis
Term
Oxytocin
Definition
Hypothalamus but stored in posterior pituitary; stimulates uterine contraction during labor; milk secretion during lactation
Term
Vasopressin (ADH)
Definition
Hypothalamus/stored in posterior pituitary: stimulates water reabsorption in the kidneys
Term
Thyroid hormones
Definition
Thyroid/ stimulates metabolic activity
Term
Calcitonin
Definition
Thryoid/ decreases blood calcium level
Term
PTH?
Definition
Parathyroid hormone in parathyroid/ increases the blood Ca level
Term
Glucocorticoids?
Definition
Source is adrenal cortex/ increases blood glucose level and decreases protein synthesis
Term
Mineralocorticoids
Definition
In adrenal cortex; increases water reabsorption in the kidneys
Term
Epinephrine, and norepinephrine
Definition
In adrenal medulla/ increases blood glucose level and heart rate
Term
Glucagon?
Definition
In pancreas; stimulates conversion of glycogen to glucose in liver, increases blood glucose
Term
Insulin?
Definition
in pancrease/ lowers blood glucose, increases glycogen stores
Term
somatostatin
Definition
Pancreas; supression of secretion of glucagon and insulin
Term
Testosterone
Definition
In testes; maintains male secondary sexual characteristics
Term
Estrogen
Definition
In ovary/placenta; maintains female secondary sexual characteristics
Term
Progesterone
Definition
Overy/placenta; promotes growth/maintenance of endometrium
Term
Thymosin
Definition
In Thymus; stimulates T lymphocyte development
Term
What is the resting potential in terms of Na+ and K+?
Definition
3 Na+ pumped out for every 2K+ pumped in
Term
What state are the gates in at rest?
Definition
closed
Term
What state are the gates in during depolarization
Definition
Na+ gates are open
Term
What state are the gates in, in repolarization?
Definition
Na+ gates close, K+ gates open
Term
What state are the gates in during hyperpolarization?
Definition
All gates are closed
Term
What are the four stages of the menstrual cycle?
Definition
1) Follicular: FSH causes growth of a follicle
2) Ovulation: LH causes follicle to release egg
3) Luteal: corpus luteum forms
4) Menstruation: endometrial lining sheds
Term
What do we call cells that produce an Rh factor? Do they produce an antibody?
Definition
Rh+, they produce no antibody
Term
What do we call cells that do not have an Rh factor?
Definition
Rh-, lack antigen and produce an antibody
Term
What are the components of the forebrain?
Definition
Telencephalon and diencephalon
Term
Name the four lobes into which the telencephalon can be divided
Definition
frontal, parietal, temporal, and occipital
Term
What part of the brain does the cerebral cortex belong to? What does it do?
Definition
To the telencephalon. It processes and integrates sensory input and motor responses. also important for memory and creative though.
Term
What portions can the diencephalon be divided into?
Definition
Thalamus and hypothalamus
Term
What is the thalamus do?
Definition
Relay and integration center for spinal cord and cortex.
Term
What does the hypothalamus do?
Definition
Controls visceral functions like hunger, thirst, sex drive, water balance, BP, and temp regulations
Term
What's function of midbrain?
Definition
Relay center for visual and auditory impulses; important role in motor control
Term
What does the hindbrain consist of?
Definition
Cerebellum, pons, and medulla
Term
What's the fcn of the cerebellum?
Definition
Modulates motor impulses initiated by motor cortex; maitenance of balance, hand-eye coordination, rapid movements
Term
What is the fcn of the pons?
Definition
Acts as relay center to allow cortex to communciate w/ cerebellum.
Term
What is the purpose of medulla?
Definition
controls vital functions, like breathing, heart rate, gastrointestinal activity, etc.
Term
What does the brainstem consist of?
Definition
Midbrain, pons, and medulla
Term
Describe RNA processing in a prokaryotic cell.
Definition
Simple RNA processing; no splicing
Term
Describe RNA processing in a eukaryotic cell
Definition
Post-transcriptional RNA modifications: splicing, 5' cap, poly-A tail
Term
Do prokaryotic cells have a cytoskeleton? What about centrioles?
Definition
No, neither.
Term
How is the mitochondria different from other membrane-bound organelles in the eukaryotic cell?
Definition
They contain their own circular DNA, ribosomes, and are capable of producing some proteins. Genome and ribosomes are more similar to prokaryotes than eukaryotes.
Term
The mitochondrial DNA a person has is identical to that of his or her _______.
Definition
Mother; a zygote recieves all its organelles from its mother.
Term
Describe Smooth ER.
Definition
Has no ribosomes on the outer surface and is involved in lipid synthesis and detoxification of drugs and poisons.
Term
What about rough ER?
Definition
Has ribosomes on its outer surface and is involved in protein synthesis.
Term
The _____ _______ synthesizes lysosome's membrane and hydrolytic enzymes
Definition
Rough ER
Term
Describe peroxisomes.
Definition
They contain oxidative enzymes that catalyze reactions in which hydrogen peroxide is produced and degraded. They break down fats into small molecules and are also used in the liver to detoxify potentially harmful compounds like alcohol.
Term
What is the cytoskeleton?
Definition
A network of specialized proteins that provides a framework for the maintainence of cell's shape. Also involved in cell movement and movement of organelles within the cell.
Term
What are the three protein filaments that make up the cytoskeleton?
Definition
microfilaments, microtubules, and intermediate filaments.
Term
What are microfilaments?
Definition
They consist of 2 intertwined strands of actin. They are involved in muscle contraction, along w/ myosin.
Term
What are intermediate filaments?
Definition
Consist of fibrous proteins coiled into thicker cables. Function in structural support of a cell.
Term
What are microtubules?
Definition
Hollow rods composed of two types of tubulin; involved in movement of organelles and chromosomes, maintenance of cell shape and cell motilitiy.
Term
What type of junction forms a total barrier to transport and diffusion?
Definition
Tight junctions
Term
What type of junctions are subject to mechanical stress?
Definition
Anchoring junction (ex: desmosomes in epithelial cells in skin)
Term
What type of junction provides a direct connection between the cytoplasm of one cell and cytoplasm of another cell via channels?
Definition
Gap
Term
Are viruses considered living organisms? What is a bacteriophage?
Definition
No; can't carry out metabolism outisde of a host cell. Bacteriophages are viruses that infect bacteria.
Term
What type of organism is fungi?
Definition
Eukaryotic but lack chlorophyll; they have membrane bound organelles.
Term
Plasmids replicate _______ of the bacterial chromosome.
Definition
independently
Term
Obligate anaerobes?
Definition
Cannot survive in the presence of oxygen.
Term
Facultative aerobes?
Definition
Can survive with or without oxygen.
Term
Obligate aerobes?
Definition
Require oxygen to survive.
Term
A single mRNA that contains more than one coding region is ________. What types of organisms is this found in?
Definition
Polycistronic; prokaryotes
Term
What are the 3 ways in which prokaryotes transfer genetic material?
Definition
Transformation, transduction, and conjugation
Term
Describe transformation.
Definition
DNA is taken up from the environment and integrated into the bacterial genome.
Term
What happens during transduction?
Definition
Bacterial genes are transferred from one bacterial cell to another by a virus.
Term
What happens during conjugation?
Definition
Genetic info is directly transferred from one bacterial cell to another via a temporary connection known as a conjugation bridge.
Term
What happens when a DNA virus infects a host cell?
Definition
viral DNA is replicated and viral mRNA is transcribed w/in the host cell's nucleus for eukaryotes and in nuclear region for prokaryotes, using the cell's own DNA polymerases, RNA polymerases, and nucleotides. Those that do this in the cytoplasm must bring their own DNA and RNA polymerases.
Term
What happens when an RNA virus infects a host cell?
Definition
viral RNA is replicated and transcribed in the cytoplasm. RNA replicase transcribes new RNA from the RNA template; some viruses bring their own RNA replicase w/ them into the host cell.
Term
What type of virus brings RNA that is first copied into DNA which integrates into the genome of the host cell? Does this escape immune detection?
Definition
Retroviruses; yes, it does since the virus integrates in the genome of the host.
Term
Describe the lytic cycle for a bacteriophage?
Definition
Viral DNA is translated and transcribed and new phages are made. The bacteriophage produces enzymes that digest the cell wall, so that cell bursts.
Term
What is the lysogenic cycle?
Definition
Viral DNA is integrated into bacterial genome in prophage form; remains dormant for one or more geneartions. Prophage can enter the lytic cycle either spontaenously or result of environmental factors.
Term
What type of fungi are molds?
Definition
Filamentous fungi and some are imperfect and can reproduce only asexually.
Term
What is a yeast?
Definition
A unicellular fungi that reproduce via budding.
Term
What is the purpose of lacteals?
Definition
Collect fats from the small intestine and transport them to circulatory system.
Term
What is each alveolus coated with? What is its function?
Definition
Surfactant: fluid that reduces surface tension along the alveoli and facilitates gas diffusion across the membrane. It helps alveolar collapse during exhalation.
Term
After oxygen passes through surfactant, what else must is pass through before entering the capillary?
Definition
Pass through alveolar and capillary membranes.
Term
___ in the alveoli flows down its partial pressure gradient from the _____ to the ______ ______ where it can bind to _____ for transport. Meanwhile, _____ flows down its partial pressure gradient from the _____ into the ______ for expansion.
Definition
O2, alveoli, pulmonary capillaries, hemoglobin, CO2, capillaries, alveoli
Term
Through panting, what happens to blood temperature?
Definition
It lowers because the increased respitory rate maximizes the area of upper respiratory surfaces that comes into contact with air from outside.
Term
The diaphragm is _____ when relaxed and is _______ when contracted.
Definition
Curved; and flattens.
Term
What are the two events that occur during inhalation?
Definition
Diaphragm contracts and flattens out, increaseing size of chest cavity. External intercostal muscles contract moving the rib cage up and out.
(Negative pressure breathing)
Term
What happens during exhalation?
Definition
Diaphragm relaxes, curving upwards.
External intercostal muscles relax; size of chest cavity decreases as air is forced out of the alveoli as lungs deflate.
Term
Is inhalation an active process? What about exhalation?
Definition
Inhalation is active, while exhalation is mostly passive except for times of strenuous activity.
Term
Where does RNA polymerase bind to DNA during transcription?
Definition
On the promoter site at the TATA boxes. It only binds to one template strand (one strand of DNA is used at a time)
Term
What are two types of base substitutions?
Definition
Transition (subsitution of a pyrimidien by a pyrimdine)
Transvesion: substituion of a purine by a pyramdine or vice versa.
Term
What are two types of chromosomal abnormalities?
Definition
1) Numerical: gain or loss of complete chromosome
2) Structural: formation of abnormal chromosomes through the misrepair of chromosome breaks or a malfunction in recombination.
Term
What are operons? What do they consist of?
Definition
Set of prokaryotic genes that form a related or coordinated function: have 3 parts: promoter region where RNA polymerase binds to initiate transcription, operator where a repressor protein to prevent transcription, and gene cluster.
Term
Why isn't mitochondrial DNA from the father passed down to the offspring?
Definition
Mitochondria from the sperm by destroyed by the egg after fertilization leaving only materinal mtDNA originally found in the unfertilized egg.
Term
What are the two hormones which reduce in level upon mensturation?
Definition
Estrogen and progesterone
Term
Would the removal of ovaries affect LH and FSH levels?
Definition
No, only leaves women devoid of estrogen and progesterone. Not the gonadotropic hormones.
Term
Do ectodermal cells possess positional information?
Definition
No. If ectodermal cells are transferred from one region to another, they develop by induction of mesodermal cells below them.
Term
T/F Mitosis and meiosis I are preceded by DNA replication, but Meiosis II is not preceded by DNA replication.
Definition
true
Term
What type of cells are involved in humoral immunity?
Definition
B cells or B lymphocytes
Term
What are memory cells?
Definition
Remember antigen, spped up secondary response.
Term
What are B lymphocyte plasma cells?
Definition
They make and release antibodies which induce antigen phagocytosis
Term
What is the difference between active and passive immunity?
Definition
Active: antibodies are produced during an immune response
Passive: antibodies produced by one organism are transferred to another organism
Term
What is the action of cytotoxic T cells?
Definition
They destroy cells directly
Term
What is the purpose of helper T cells?
Definition
Activate B adn T cells and macrophages by secreting lymphokines.
Term
What's the action of suppressor cells?
Definition
Type of T lymphocyte that regulates B adn T cells to decrease anti-antigen activity.
Term
In the proximal convoluted tubule, what solutes are actively transported out?
Definition
Sodium, amino acids, vitamins, glucose
Term
Which components are passively diffused out of the proximal convoluted tubule? Which components actively enter it?
Definition
Chloride, water passively diffusion out.
Potassium, H, NH3, and urea are actively placed inside it.
Term
What is removed in the descending loop of Henle? Is it by active or passive transport?
Definition
Water is passively diffused out.
Term
What is passively diffused out of the inner medulla?
Definition
Sodium and chloride ions
Term
What components are removed from the ascending loop of Henle?
Definition
Sodium and chloride ions are now actively removed
Term
How is the distal convouted similar to the proximal convoluted tubule?
Definition
Potassium, hydrogen, and ammonia are actively placed in it; and water is passively diffused out.
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