Final Exam Study Guide on Principles of Biology I | BIOL 1107, Study notes of Biology

Download Final Exam Study Guide on Principles of Biology I | BIOL 1107 and more Study notes Biology in PDF only on Docsity! Study Guide: Exam III Chapter 41, Introduction to Animal Structure 1. How do the functions of the body as a whole (breathing, eating, elimination of wastes, etc.) relate to the processes that occur in single cells? Correlations btwn form and function start at the molecular level, correlations btwn structure and function occurs at the level of the cell, and the overall shape of a cell correlates with its bigger picture function. 3. How are osteocytes able to attain oxygen and nutrients? You must consider the organization of hard bone in which osteocytes are trapped. The bone has an organization of canals that thread through the bone. The canals carry blood vessels and nerves. The canal is called the "Haversain Canal” Osteocytes are organized in a solar system like arrangement around the Haversain canal. The osteocytes have tiny threads of cytoplasm that intertwine. The tiny threads of cytoplasm are called canaliculi; the closest osteocytes obtain oxygen via diffusion of the gas from the blood vessel. The further you get from the canal, the lower the concentration of oxygen. Therefore, the oxygen continues to diffuse from the canaliculi of one cell to the cytoplasm of the cell further from the blood vessel. Osteocytes receive nutrients from the canaliculi attached to the central canal, that brings in through the small microtubular tunnel and goes to osteocytes via gap junctions. 4. Why is blood considered a connective tissue? (1) Embryologically, it has the same origin (mesodermal) as do the other connective tissue types and (2) blood connects the body systems together bringing the needed oxygen, nutrients, hormones and other signaling molecules, and removing the wastes. Chapter 41, Bioenergetics 1. How does body size affect animal physiology? As an organism’s size increases, its mass-specific basal metabolic rate must decrease. Otherwise the surface area available for exchange of materials would fail to keep up with the metabolic demands generated by the enzymes in the organism. (small animals live fast b/c they have enough surface area to support rapid metabolism, where large animals live slow b/c they don’t have enough surface area to keep up). -Adaptations that increase surface area: 1) Flattening (fish gill lamellae) 2) Folding (intestinal folds and villi) 3) Branching (capillaries) 2. Distinguish between basal metabolic rate and standard metabolic rate. The standard metabolic rate is overall rate of energy consumption by an individual, the basal rate is the rate at which an animal consumes oxygen while at rest, with an empty stomach, under normal temperature and moisture conditions. 3. Describe the location and function of interstitial fluid. Fluid surrounding the cells in body tissues; provides a path through which nutrients, gases, and wastes can travel between the capillaries and the cells. 4. What is the difference between negative feedback and positive feedback? What are the components of a feedback circuit? What are some examples of positive feedback and negative feedback? -Positive feedback: a mechanism in which a change in some variable stimulates a response that increases the change. Relatively rare in organisms, but is important in the generation of the action potential. -Negative feedback: a self-limiting, corrective response in which a deviation in some variable (ex, body temp, blood pH) triggers responses aimed at returning the variable to normal. 5. What is homeostasis? How does homeostasis relate to positive and negative feedback? Homeostasis: stability in the chemical and physical conditions within an animal’s cells, tissues and organs. Achieved through conformation and regulation. Homeostatic systems are based on negative feedback. -3 major components, 1) sensor (senses) 2) integrator (evaluates) 3) effector (restores) Chapter 43, Animal Nutrition 1. What is the difference between undernourishment and malnourishment? Can a person be both obese and malnourished at the same time? What are some of the risks of obesity? Undernourishment means someone isn't getting enough of any type of food; malnourishment means they're eating stuff that's bad for them, AS WELL AS not having enough to eat. A person CAN be obese and malnourished if they are eating too much of the wrong things. 2. What is the difference between an essential nutrient and a nonessential nutrient? What are the four classes of essential nutrients? The essential nutrients your body requires include vitamins, minerals, proteins, carbohydrates, fats (essential fatty acids), water and oxygen that we need to get from food. Non-essential nutrients are nutrients that your body can produce internally. -Essential nutrients: Essential amino acids (proteins), Essential fatty acids (fats), Vitamins – 13 vitamins, both water-soluble and fat-soluble, Minerals – inorganic nutrients, such as calcium and phosphorus. 3. What are the two categories of vitamins? Which group is most easily stored in the body? What is the most common function of vitamins? The 13 vitamins are categorized into two major classes; those that can dissolve in water, called water-soluble vitamins, and those that can dissolve in fat or oil, called fat- soluble vitamins. The water-soluble vitamins, found in fruits and vegetables, cannot be stored in the body so they must be obtained regularly in the diet. The fat-soluble vitamins, A, D, E and K, can be stored in body tissues so they do not need to be eaten as frequently as water-soluble vitamins. Vitamins are, however, vital to the growth, maintenance and function of the human body. 4. Vitamin C is necessary for the formation of collagen. How does a vitamin C deficit lead to the symptoms of scurvy? What are the diseases arising from deficiencies of vitamin B1 and vitamin D? What are the symptoms of these diseases? Without vitamin C you don't make collagen, essential to connective tissue, so your gums bleed, teeth loosen, joints and muscles ache, and eventually you die. Beriberi is a disease in which the body does not have enough thiamine (vitamin B1). Symptoms: pain or tingling in the arms or legs, decreased reflex activity, fluid accumulation in the arms and legs, enlargement of the heart, constipation, and nausea and vomiting. Rickets is a disorder caused by a lack of vitamin D, calcium, or phosphate. It leads to enzymes, and enterogastrone. The chyme passes out of the stomach with an acid reaction, and its undigested constituents are at once subjected to a second process of digestion in the duodenum by an alkaline fluid, which is a mixture of the pancreatic juice, the bile, and the enteric juice. The pancreatic juice converts the remaining starch into sugars, and the remaining proteins into peptones, leucin, tyrosine, and fatty acids; whilst in association with the bile it partly emulsifies and partly saponifies the fats. The sugars are converted into lactic acid and butyric acid,. These products of duodenal digestion, as well as those of gastric digestion, are absorbed into the portal and lymphatic systems; whilst the undigested portions of the food and various excretions are further acted on by the bowel, and become the feces. Just as the acid gastric juice was stimulated to flow by the alkaline reaction of the insalivated food, so the three great alkaline secretions entering the intestine are stimulated to flow by the acid chyme. Moderate acidity of the contents, as they enter the duodenum, is manifestly the most favorable to intestinal digestion, excessive acidity tending to neutralize the alkaline fluids, and render them inert. 7. Describe how pancreatic zymogens for proteolytic enzymes are activated in the duodenum and include the role of the intestinal enzyme enteropeptidase. Pancreatic zymogens are normally only activated after they reach the small intestine. A brush border enzyme, enterokinase, cleaves a peptide from trypsinogen, forming the active enzyme trypsin. Trypsin then activates the other enzymes. Enteropeptidase is an enzyme of the intestinal juice that activates the proteolytic enzyme of the pancreatic juice by converting trypsinogen into trypsin. 8. Where does most nutrient absorption occur? Why are the many folds, villi, and microvilli important for nutrient absorption? The small intestine is the body's major digestive organ. Virtually all absorption occurs there. The purpose of villi, microvilli and the circular folds is to increase the area of absorption within the small intestine. 9. Sugars and amino acids that are absorbed are immediately transported to the liver, while fats are not directly transported to the liver. What is the anatomical reason for this? The digestion of fats starts with the action of bile. This emulsifies lumps of fat into thousands of tiny droplets, allowing the enzyme lipase to break the fats down into glycerol and fatty acids. Lipase is released from the pancreas and digests fat in the small intestine. Fats are not soluble in water, but glycerol and fatty acids are, and they are easily absorbed into the body. 10. Where does most reabsorption of water occur? What is the main source of vitamin K for humans? Water is filtered and then reabsorbed by osmosis. The major site of water reabsorption is the proximal tubule. In the proximal tubule water is absorbed osmotically with ions In the loop of Henle, ion and water reabsorption occur in different limbs. In the loop of Henle more ions are reabsorbed than water, so the medulla becomes concentrated and the tubular fluid becomes dilute. There is no significant water reabsorption in the distal tubule. In the collecting ducts water can leave the ducts to enter the medullary interstitium ADH controls the insertion of aquaporin water channels which are necessary for water reabsorption in the collecting duct. The posterior pituitary makes ADH. Vitamin K- green leafy vegetables. Chapter 44, Gas Exchange 1. What effects the amount of oxygen in a solution? 1.The solubility of the gas in water. 2.The temperature of the water. 3.The presence of other solutes. 4.The partial pressure of the gas in contact with the water. 2. For the human respiratory system, describe the movement of air through air passageways to the alveolus, listing the structures it must pass through on the journey. Pathway of air: nasal cavities (or oral cavity) > pharynx > trachea > primary bronchi (right & left) > secondary bronchi > tertiary bronchi > bronchioles > alveoli (site of gas exchange) 3. Define negative pressure breathing, and explain how respiratory movements in humans ventilate lungs. Negative pressure is caused in humans by the contraction of the diaphragm, and the relaxation of intercostal muscles, increasing the volume of the thoracic cavity, which the lungs expand to fill. 4. Define the following lung volumes: Tidal volume, vital capacity, and residual volume. Tidal volume is the lung volume representing the normal volume of air displaced between normal inspiration and expiration when extra effort is not applied. Vital capacity is the maximum amount of air a person can expel from the lungs after a maximum inspiration. Residual volume: The amount of air left in your lungs when you have exhaled as far as you can. 5. Explain how breathing is controlled. Breathing is usually automatic, controlled subconsciously by the respiratory center at the base of the brain. 6. Describe how oxygen moves from the alveolus into the capillary, and explain why a pressure gradient is necessary. Oxygen diffuses from the alveoli into the blood due to higher PO2 (partial pressure of oxygen) levels in the alveoli than in the blood. 7. Describe the structure of hemoglobin, explain the result of cooperative binding, and state how many oxygen molecules a saturated hemoglobin molecule can carry. •Red blood cells contain an oxygen-carrying molecule called hemoglobin. •Hemoglobin consists of four polypeptide chains, each of which binds to a nonprotein group called a heme. •Each heme contains an iron ion (Fe2+) that can bind to an oxygen molecule. Each hemoglobin molecule can thus bind up to four oxygen molecules. •In blood, 98.5 percent of the oxygen is bound to hemoglobin. •Cooperative binding makes hemoglobin exquisitely sensitive to changes in the Po2 of tissues. •In other words, in response to a relatively small change in tissue Po2, there is a relatively large change in the percentage saturation of hemoglobin. 8. How is carbon dioxide picked up from the tissues and deposited in the lungs. What is the role of carbonic anhydrase? •CO2 that is produced by cellular respiration enters the blood and RBCs, where it is quickly converted to bicarbonate ions and protons in a reaction catalyzed by the enzyme carbonic anhydrase. •Carbonic anhydrase catalyzes the formation of carbonic acid from carbon dioxide in water. –Consequently, CO2 that diffuses into red blood cells is quickly converted to bicarbonate ions and protons. –Thus, most CO2 is transported in blood (specifically in plasma) in the form of the bicarbonate ion, HCO3. 9. Explain how hemoglobin acts as a buffer. Hemoglobin binds to H+ ions when they are in high concentration and releases them when they are in low concentration Chapter 44, Circulation 1. Distinguish between an open and a closed circulatory system. How does hemolymph differ from blood? Vertebrates, and a few invertebrates, have a closed circulatory system. Closed circulatory systems have the blood closed at all times within vessels of different size and wall thickness. In this type of system, blood is pumped by a heart through vessels, and does not normally fill body cavities. Has high hemolymph. The open circulatory system is common to mollusks and arthropods. Open circulatory systems pump blood into a hemocoel with the blood diffusing back to the circulatory system between cells. Blood is pumped by a heart into the body cavities, where the blood surrounds tissues. Has low hemolymph. 2. Distinguish between pulmonary and systemic circuits. What is the function of each? Compare and contrast the circulatory systems of fish, amphibians, and mammals. –The pulmonary circulation is a lower-pressure circuit to and from the lungs. –The systemic circulation is a higher-pressure circuit to and from the rest of the body. •The pulmonary and systemic circulations are completely separated in the four- chambered hearts of birds and mammals, but are only partially separated in the three- chambered hearts of amphibians and the “five-chambered” hearts of turtles and lizards. 1. The metabolism of which molecules produces ammonia? •Ammonia (NH3) is a by-product of catabolic reactions. Ammonia is a strong base; it readily gains a proton to form an ammonium ion (NH4+). This ion is eventually toxic to cells. •Different species get rid of ammonia safely and efficiently in different ways. •Humans convert ammonia to less toxic urea and excrete it in urine. •Birds, reptiles, and terrestrial arthropods convert ammonia to uric acid, which can be excreted as a dry paste. 3. Distinguish between an osmoconformer and osmoregulator. Why is this important do know? Osmoconformers are animals that allow their body fluid concentration to vary with the environment. An example are marine fish. By drinking in sea water, and actively excreting salt out from the gills, the fish will gain salt as it produces an isotonic urine. Omoregulators are more common in the animal kingdom. Osmoregulators actively control salt concentrations despite the salt concentrations in the environment. An example are freshwater fish. The gills actively uptake salt from the environment. Water will diffuse into the fish where the fish will excrete a very hypotonic urine to expel all the excess water. 4. Define hypo-osmotic, hyper-osmotic, and isoosmotic. Would water flow into or out of a hypo- osmotic solution? Hypo-osmotic: containing a lower concentration of osmotically active components than a standard solution. Hyper-osmotic: pertaining to a solution that has a higher solute osmotic gradient because water leaves the descending limb and salt leaves the ascending limb. 6. What is the osmolarity of the filtrate at the distal tubule? How does this compare to the osmolarity in the loop of Henle? •Once filtrate has passed through the loop of Henle, it enters the distal tubule. This fluid is slightly hypotonic to blood, and the solutes it contains are mainly urea and other waste products. •The fluid that enters the distal tubule is relatively constant in composition over time. In contrast, the urine that leaves the collecting duct is highly variable in osmolarity and in Na+ and Cl concentration. 7. How does the countercurrent arrangement between the nephron and vasa recta help maintain the concentration of salts in the renal medulla? •The water and salt that move out of the loop quickly diffuse into the vasa recta, the associated network of blood vessels. •As a result, water and electrolytes are returned to the body. 8. Where can urea leave the filtrate? How does this contribute to the process of water retention? 9. How does the hypothalamus regulate the amount of water loss in urine? 10. How does the kidney contribute to homeostasis in blood osmolarity and blood pressure? - osmolarity- blood volume- affects blood pressure 11. Hormones have important roles in osmoregulation. What is the role of the following: antidiuretic hormone and angiotensin II? ADH saves water. Chapter 42, Osmoregulation 1. What are the two modes of reproduction? What are some of the advantages of each? Asexual and sexual… produce both ways: daphnia 2. What are some of the modes of asexual reproduction? •In budding, an offspring begins to form within or on a parent; the process is completed when the offspring breaks free and begins to grow on its own. The offspring is a miniature version of the parent. •In fission, an individual simply splits into two or more descendants. •In parthenogenesis, female offspring develop from unfertilized eggs. These offspring are genetically identical to the mother. Hermaphroditism is a group of conditions where there is a discrepancy between the external genitals and the internal genitals (the testes and ovaries). 5. Be able to describe the pathway a sperm travels through the male reproductive tract starting with spermatogenesis. The testes are where sperm are manufactured in the scrotum. The epididymis is a tortuously coiled structure topping the testis, and it receives immature sperm from the testis and stores it several days. When ejaculation occurs, sperm is forcefully expelled from the tail of the epididymis into the deferent duct. Sperm then travels through the deferent duct through up the spermatic cord into the pelvic cavity, over the ureter to the prostate behind the bladder. Here, the vas deferens joins with the seminal vesicle to form the ejaculatory duct, which passes through the prostate and empties into the urethra. When ejaculation occurs, rhythmic muscle movements propel the sperm forward. 6. What are the accessory glands? What does each contribute to semen? The paired seminal vesicles are saccular glands posterior to the urinary bladder. The fluid from the seminal vesicles is viscous and contains fructose, which provides an energy source for the sperm; prostaglandins, which contribute to the mobility and viability of the sperm; and proteins that cause slight coagulation reactions in the semen after ejaculation. The prostate gland is a firm, dense structure that is located just inferior to the urinary bladder. Numerous short ducts from the substance of the prostate gland empty into the prostatic urethra. They function to enhance the motility of the sperm. Bulbourethral glands are small, about the size of a pea, and located near the base of the penis, the bulbourethral glands secrete an alkaline mucus-like fluid. This fluid neutralizes the acidity of the urine residue in the urethra, helps to neutralize the acidity of the vagina, and provides some lubrication for the tip of the penis during intercourse. Seminal fluid, or semen, is a slightly alkaline mixture of sperm cells and secretions from the accessory glands. Chapter 48, Reproduction 1. What are the structures in the female reproductive system? Be able to trace the movement of an egg through the reproductive tract. Which structures are necessary for producing gametes, and which are necessary for supporting a developing embryo? –Eggs are produced in the paired ovaries. –During ovulation, an egg is expelled from the ovary and enters the oviduct (fallopian tube), where fertilization may take place. –Fertilized eggs are then transported to the uterus. 2. What are the steps of spermatogenesis? What are the steps in oogenesis? How do spermatogenesis and oogenesis differ? In which stages of meiosis is there a pause in development of an ovum? What signals cause meiosis to resume in a developing ovum? What are polar bodies? Spermatogenesis: 1) meiosis, during which the number of chromosomes in the cell is reduced to half or 23 chromosomes each; 2) meiosis II, during which each haploid cell forms spermatids; and 3) spermiogenesis, during which each spermatid develops into a sperm cell with a head and tail. Oogenesis: begins during fetal development. Meiosis I occurs prior to birth, and then development of the primary oocytes is suspended until puberty. The secondary oocyte is released at ovulation in response to hormonal secretions. If fertilization occurs, meiosis II resumes and an ovum is formed. 3. What are the hormonal signals that govern spermatogenesis? What are the feedback systems regulating the levels of FSH and LH? a. Testosterone i. produced by Leydig cells ii. Androgen iii. Promotes Sertoli cell function b. Estradiol i. Produced by Sertoli cells c. Inhibin i. Produced by Sertoli cells ii. FSH levels in males is decreased by inhibin d. FSH—follicle stimulating hormone i. Produced by anterior pituitary ii. FSH regulates the mitotic divisions and efficiency of type A spermatogonia development iii. FSH controls entry of stem cell type A spermatogonia into proliferating pool iv. The yield of spermatozoa is increased by FSH by preventing the degeneration of differentiating A type spermatogonia v. FSH is necessary during development: required to establish Sertoli cell function e. LH—lutenizing hormone i. Produced by anterior pituitary ii. Increases testesterone production by Leydig cells f. GnRH—gonadotropic releasing hormone i. Hypothalamic hormone that controls release of anterior pituitary hormones (LH and FSH)- regulates them 4. What are the differences between an estrous cycle and a menstrual cycle? What are the three phases of the menstrual cycle? -The estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Humans and great apes undergo a menstrual cycle instead. Mammals share the same reproductive system, however, species vary significantly in the detailed functioning. One difference is that animals that have estrous cycles reabsorb the endometrium if conception does not occur during that cycle. Animals that have menstrual cycles shed the endometrium through menstruation instead. Another difference is sexual activity. In species with estrous cycles, females are generally only sexually active during the estrous phase. This is also referred to as being "in heat." In contrast, females of species with menstrual cycles can be sexually active at any time in their cycle, even when they are not about to ovulate. -Menstrual cycle has 3 stages: menstruation, follicular phase and luteal phase 5. What are the stages in the ovarian cycle? What is the function of the corpus luteum? How do the stages of the ovarian cycle relate to the stages in the menstrual cycle? The ovarian cycle starts on the first day of the menstrual cycle. The menstrual cycle begins on the first day of the periods - which is the first day of bleeding. At this time, the levels of all the hormones – estrogen, progesterone , FSH and LH - which are primarily responsible for maintaining menstruation, are at the baseline levels. The ovarian cycle is then divided into 2 phases: follicular and luteal. The corpus luteum secretes progesterone & other hormones to maintain early pregnancy 6. What are the hormones that control the menstrual and ovarian cycles? What signals cause the spike in LH and FSH? Which of these hormones does the developing follicle respond to during the follicular phase of the ovarian cycle? Which hormone induces ovulation? What is the source of estrogen and progesterone during the luteal phase of the ovarian cycle? During your menstrual cycle, GnRH is released first by the hypothalamus. This causes a chemical reaction in the pituitary gland and stimulates the production of FSH and LH (peak just prior to ovulation). Estrogen, progesterone, and testosterone are produced by the ovaries in reaction to stimulation by FSH and LH. Estradiol responds during the follicular phase. LH induces ovulation. 7. What is menopause? A gradual process that happens when a woman's ovaries make less estrogen and progesterone and her lifetime supply of eggs is depleted. A woman is considered to have