MCAT Biology Revision Questions with Complete Verified Solutions

1. What are peroxisomes - Ans Break down fatty acids with beta-oxidation 2. Difference between stratified and pseudostratified epithelia - AnsStratified: multiple layers Pseudo: one layer with a bunch of different heights 3. Difference between cocci, bacilli, and spirilli - AnsCocci: sphere bacteria Bacilli: rod-shaped bather Spirilla: spiral bacteria 4. Difference between obligate aerobes, obligate anaerobes, facultative anaerobes, aerotolerant anaerobes - AnsObligate aerobes: need O2 Obligate anaerobes: cannot survive in O2 Facultative anaerobes: can do aerobic and anaerobic Aerotolerant: can surge with O2 but can only do anaerobic 5. Difference between gram+ and gram-bacteria - Ans+ have a thick cell wall composed of peptidoglycan and lipoteichoic acid -thin cell wall with peptidoglycan but also phospholipids and lipopolysaccharides 6. What is chemotaxis - AnsBacteria moving in repose to chemical stimuli 7. What is an episome - AnsPlasmids that can integrate into the genome 8. Difference between transformation, conjugation, transduction, and transposons - AnsTransformation: new genetic material integrated into a genome Conjugation: the transfer of genetic material through a conjugation bridge Transduction: the transfer of genetic material through a bacteriophage vector Transposing: genetic elements that can alone insert or remove into a genome 9. Parts of a virus - AnsCapsid shell, tail sheath that objects, and tail fibers that attach to a cell 10. Difference between positive and negative sense virus - Ans+ translated by host cell - RNA replicate must go first then translated 11. Difference between prions and viroids - AnsPrions: infection proteins that trigger misfiring of other proteins Viroids: plant circular pathogens 12. Functions of the smooth ER - AnsLipid synthesis, poison detox, transport of proteins 13. Where is sperm developed - AnsSeminiferous tubules in the testes, nourished by Sertoli cells 14. Difference between prostate and bulbourethral glands - AnsProstate produces alkaline fluid, bulbourethral produces fluid that cleans out any remaining urine and lubricates for sex 15. Steps of spermatogenesis - Ans1. S phase: primary spermatocytes 2. Meiosis I: secondary spematocytes 3. Meiosis II: spermatids 4: maturation: spermatozoa 16. Steps of oogenesis - Ans1. Prophase I: primary oocytes 2. Metaphase II: secondary oocytes 3. Meiosis II: only completed if fertilized 17. What triggers oogenesis and what triggers spermatogenesis - AnsOogenesis: follicle stimulating hormone (FSH) stimulates development of ovarian follicles, luteinizing hormone( LH) causes ovulation Sperm: FSH stimulates Sertoli cells and spermoneogeneis. LH triggers testosterone production 18. Menstrual cycle steps - AnsFollicular phase: FSH and LH secretion, estrogen is released Ovulation: sudden surge in LH (estrogen switches from negative to positive feedback) Luteal phase: secretion of progesterone (peak) Menstruation: estrogen and progesterone levels drop 19. What phase does ovulation occur - AnsMetaphase II 20. Where does fertilization occur? - Ansin the ampulla of the fallopian tube 21. Steps of fertilization - Ans1. the sperm establishes the acrosomal apparatus, injects its pronucleus 2. calcium ions are released to prevent other sperm from penetrating 3. the metabolic rate of the diploid zygote increases, called the cortical reaction 22. what is the difference between a zygote and an embryo - Ansembryo is the result of the first zygote cleavage (no longer unicellular) 23. difference between determinate and indeterminate cleavage - Ansindeterminate: results in cells that are capable of becoming any kind of cell determinate: cells that are committed to differentiating into a specific type of cell 24. Describe the parts of a blastula - Anshas a fluid filled center called a blastocoel and has two different cell types, including trophoblasts (placenta) and the inner cell mass(developing organism) 25. how do we go from blastula to fetus - Ans1. blastula implants in the endometrial lining and forms the placenta 2. chorion contains chorionic villi, which penetrates the endometrium and create the interface between materal and fetal blood 3. amnion lies just inside the chorion and produces amniotic fluid