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Test your basic knowledge |
MCAT Prep Biology
Start Test
Study First
Subjects
:
mcat
,
science
Instructions:
Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can
study here
.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.
This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.
1. Steroid hormones secreted from the adrenal cortex. The two major classes are teh mineralocorticoids and glucocorticoids. Aldosterone is the principal mineralocorticoid - and cortisol is the principal glucorcorticoid.
Aminion
Phototroph
Gap phase
Corticosteroids
2. Movement across the membrane of a cell that does not require energy input from the cell. Passive transport relies on concentration gradients to provie the driving force for movement - and includes both simple and facilitated diffusion.
Mucocilliary escalator
Prophase II
Passive transport
Chitin
3. Specif ic defense of the body by antibodies - secreted into the blood by B- cells.
Humoral immunity
Vagus nerves
Poycistronic mRNA
Gap junction
4. A small - extrachromosomal (outside the genome) - circular DNA molecule found in prokaryotes.
Gastrulation
Lawn
Plasmid
Tendon
5. The reactants in an enzyme - catalyzed reaction. Substrate binds at the active site of an enzyme.
Microfilament
Anaphase II
Large intestine
Substrate(s)
6. A protein that is associated with the plasma membrane of a cell - but that is not embedded in the lipid bilayer. Peripheral proteins typically associate with embedded proteins through hydrogen bonding or electrostatic interactions.
Ceruminous gland
Peroxisome
Epiglottis
Peripheral membrane protein
7. A thick muscular tube that connects the epididymis of the testes to the urethra. Muscular contractions of the vas deferns during ejaculation ehp propel the sperm outward. Severing of the vas deferens (vasectomy) results in sterility of the male.
Repressor
Vas deferens
Orgasm
Organ of Corti
8. The fertilization of an oocyte by more than one sperm. This occurs in some animals - but in humans - blocks to polyspermy exist (the fast block and the slow block) so that only a single sperm can penetrate the oocyte.
Gonadotropins
Polyspermy
Homozygous
Gonadotropin releasing hormone (GnRH
9. An ion channel that is opened or closed based on the binding of a specific ligand to teh channel. Once opened - the channel allows the ion to cross the plasma membrane according to its concentration gradient. An examples is the acetylcholine receptor
Ptyalin
Plasmid
Operator
Ligand - gated ion channel
10. An integral protein that selectively allows molecules across the plasma membrane. See also entries under 'ion channel' - 'voltage - gated channel' - and 'ligand - gated channel'.
Mucocilliary escalator
Calcitriol
Thymine
Channel protein
11. Active transport that relies directly on the hydrolysis of ATP.
Sertolli cells
Atrium
Primary active transport
Heterochromatin
12. A hormone derived from cholesterol. Steroids are generally hydrophobic and can easily cross the plasma membrane of cells - thus receptors for steroids are found intracellularly. Once this steroid binds to its receptor - the receptor - steroid complex
Bowman's capsule
Epiphysis
Steroid hormone
Soma
13. A receptor that responds to changes in temperature.
Thermoreceptor
Spatial summation
Pyruvic acid
Acinar cells
14. The movement of a hydrophobic molecule across the plasma membrane of cell - down its concentration gradient. Since the molecule can esialy interact with the lipid bilayer - no additional help (such as a channel or pore) is required.
Optic disk
Epiphysis
Simple diffsuion
Ovary
15. Bacteria that have a thick peptido glycan cell wall - and no outer membrane. They stain very darkly (purple) in Gram stain.
Gram - positive bacteria
Activation energy (Ea)
Ovarian cycle
Blastocyst
16. A chemical secreted by a T cell (usually the helper Ts) that stimulates activation and proliferation of other immune system cells.
Luteinizing Hormone (LH)
Glycolipid
Kinase
Interleukin
17. The deliberate exposure of a person to an antigen in order to provoke the primary immune response and memory cell production. Typically the antigens are those normally associated with pathogens - thus if the live pathogen is encountered in the future
Anaphase I
Vaccination
Humoral immunity
Plasmid
18. The innermost layer of the eyeball. The retina is made up of a layer of photoreceptors - a layer of bipolar cells - and a layer of ganglion cells.
Retina
Fimbriae
Vital capacity
G- protein linked receptor
19. A method of DNA protection utilized by prokaryotes in which their large circular chromosome is coiled upon itself.
Channel protein
Appendix
Prophase II
Supercoiling
20. A short sequence of amino aids - usually found at the N- terminus of a protein being translated - that directs the ribosome and its associated mRNa to the membranes of the rough ER where trasnlation will be completed. Signal sequences are found on me
Determination
Downstream
MHC
Signal sequence
21. A poysaccharide found in the cell walls of fungi and in the exoskeletons of insects.
Chitin
Uterus
Monosaccharide
Capacitation
22. The nervous system of the gastrointestinal tract. It controls secretion and motility within teh Gi tract - and is linked to the central nervous system.
Smooth Endoplasmic Reticulum
Interleukin
Enteric nervous system
Urea
23. The amount of blood returned to heart by the vena cavae.
Venous returns
Hyperpolarization
Acrosome
Enterokinase
24. A nucleoside with one or more phosphate gropus attached. Nucleoside triphosphates (NTPs) are the building blocks of RNA and are also used as energy molecules - especially ATP. Deoxynucleoside triphosphates (dNTPs) are the building blocks of DNA; in t
Cecum
Nucleotide
Myofiber
Lysosome
25. A non - bony material that fills the hollow spaces inside bones. Red bone marrow is found in regiosn of spongy bone and is the site of blood cell (red and white) production. Yellow bone marrow is found in the diaphysis (shaft) of long bones - is most
Systemic circulation
Acrosome
Total lung capacity
Bone marrow
26. A series of enzyme complexes found along the inner mitochondrial membrane. NADH and FADH2 are oxidized by tehse enzymes; the electrons are shuttled down the chain and are ultimately passed to oxygen and to produce water. The electron energy is used t
Electron transport chain
Ureters
Capsid
Prosthetic group
27. An **organic molecuel taht associates non - covalently with an enzyme - and that is required for the proper functioning of the enzyme.
Hypophysis
IPSP
Thecal cells
Coenzyme
28. The second major node of the cardiac conduction system (after the SA node). The cardiac impulse is delayed slightly at teh AV node - allowing the ventricles to contract just after the atria contract.
Cervix
Large intestine
Enterogasterone
Atrioventricular (AV) node
29. The valve that controls the release of urine from the bladder. It has an internal part made of smooth muscle (thus involuntary) and an external part made of skeletal muscle (thus voluntary).
Ureters
Lag phase
Urinary sphincter
Choroid
30. The main air tube leading into the respiratory system. The trachea is made of alternating rings of cartilage and connective tissue.
Trachea
Chondrocyte
Single strand binding proteins
Inspiration
31. Aromatic bases found in DNA and RNA that are derived from purine. They have a double rightn structure and include adenine and guanine.
Purine bases
Leukocyte
Disaccharide
Heterozygous
32. The division of the autonomic nervous system known as the 'resting and digesting' system. It causes a general decrease in body activities such as heart rate - respiratory rate - and blood pressure - and an increase in blood flow to the GI tract and d
urfactant
Mesoderm
Reverse transcriptase
Parasympathetic nervous system
33. The liquid portion of blood; plasma contains water - ions - buffers - sugars - proteins - etc. Anything that dissolves in blood dissolves in the plasma portion.
Acinar cells
Log phase
Plasma
Pacemaker potential
34. One of the three primary (embryonic) germ layers formed during gastrulation. Ectoderm ultimately forms external structures such as the skin - hair - nails - and inner linings of the mouth and anus - as well as the entire nervous system.
Uterine tubes
Ectoderm
Anabolism
Chemical synapse
35. The outer ring of cells of a blastocyst. The trophoblast takes part in the formation of the placenta.
FADH2
Peptide hormone
Trophoblast
Operator
36. An organs in the abdominal cavity with two roles. The first is an exocrine role: to produce digestive enzymes and bicarbonate - which are delivered to the small intestine via the pancreatic duct. The second is an endocrine role: to secrete insulin an
Excretion
Pancreas
Homologous structures
Reflex arc
37. A trop hormone produced by the anterior pituitary gand that targets the adrenal cortex - stimulating it to relase corisol and aldosterone.
Pyruvate dehydrogenase complex
Adrenocoricotropic hormone (ACTH)
Glomerulus
Mitosis
38. A neuron that arries information (action potentials) to the central nervous system; a sensory neuron.
Diaphragm
Ligase
Afferent neuron
Insulin
39. Something that increases the rate of a chemical reaction by reducing the activation energy for that reaction. The free energy of reaction remains unchanged.
Hemizygous gene
Catalyst
Antigen presenting cell
Collagen
40. A type of white blood cell; leukocytes are either B or T cells and are involved in disease defense.
Leukocyte
Oxidative phosphorylation
Reduction
Hematopoiesis
41. Movement that is directed by chemical gradients - such as nutrients or toxins. (seen in some bacteria)
Sex- linked rait
Lymph node
Chemotaxis
Sebaceous gland
42. An organism that can only survive in the absence of oxygen (anaerobic metabolism); oxygen is toxic to obligate anaerobes.
Obligate anaerobe
Anterioir pituitary gland
Amphipathic
Tropomyosin
43. A flexible piece of cartilage in the larynx that flips downward to seal teh trachea during swallowing.
Macrophage
Epiglottis
Gap junction
Placenta
44. An RNA polymerase that creates a primer (made of RNA) initiate DNa replication. DNA pol binds to the primer and elongates it.
Primase
Organ of Corti
Internodal tract
Interneuron
45. A carrier protein that transports two molecules acrss the plasma membrane in opposite directions.
Microtubule
Antiporter
Chorion
T tubules
46. Inhibitory postsynaptic potential; a slight hyperpolarization of the postysynaptic cell - moving the membrane potential of that cell further from threshold.
Systole
Small intestine
IPSP
Sarcomere
47. The tubes that carry urine from the kindeys to the bladder.
Villi
Lag phase
Feedback inhibition
Ureters
48. A haploid but immature cell resulting from the second meiotic division f spermatogenesis. Spermatids undergo significant physical changes to become mature sperm (spermatozoa).
A site
Virus
Yolk sac
Spermatid
49. A diploid cell formed by the fusion of two gametes during sexual reproduction.
Peptide hormone
Zygote
Autoimmune reaction
Nociceptors
50. A neuron that carries information (action potentials) away from the central nervous system; a motor neuron.
Endosymbitoic theory
Monosaccharide
Diaphysis
Efferent neuron