Biology 5B Midterm 2 Study Guide
Biology 5B Midterm 2 Study Guide Bio5B
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This 13 page Study Guide was uploaded by Akash Patel on Wednesday June 15, 2016. The Study Guide belongs to Bio5B at University of California Riverside taught by Redak in Spring 2015. Since its upload, it has received 10 views. For similar materials see Biology 5B: Organismal Biology in Biology at University of California Riverside.
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Date Created: 06/15/16
ANIMAL METABOLISM AND ENERGETICS: 1. Be able to explain what regulates animal physiology (homeostasis, regulation and feedback: negative and positive) ● Homeostasis: maintenance of constant internal environment ○ body temperature, blood pH, and glucose concentration are maintained at constant level ○ stimulus: fluctuations above or below a set point; triggers response ● regulator: uses internal control mechanisms to moderate internal change in face of external, environmental fluctuation ● conformer: allows internal condition to vary with certain external changes ○ terms apply to different possible regulated functions, animals regulate somethings and not others ● negative feedback: helps return variable to normal range or set point ○ buildup of the end product shuts off system ○ signal is inverted to turn system around ■ body temp too warm, mechanism that makes heat turns around and stops making heat ● positive feedback: stimulus is external ○ signal is amplified so system keeps increasing or decreasing output ○ requires something external to stop signal ■ contractions don’t stop during childbirth, increases until baby leaves birth canal 2. Relate structure with function and identify diagrams of epithelial, connective tissue, muscle tissue, and nervous tissue ● Epithelial tissue: covers outside of the body and lines organs and cavities within the body ○ has cells closely joined and vary in shape and cell arrangement ○ Cuboidal (dice), columnar (bricks), squamous (floor tile) ● Connective tissue: binds and supports other tissues ○ has sparsely packed cells scattered throughout extracellular matrix ○ matrix has fibers in a liquid, jelly like, or solid foundation ● Muscle tissue: long cells called muscle fibers that contract in response to nerve signals ○ skeletal muscle: responsible for voluntary movement ○ smooth muscle: responsible for involuntary body activities ○ cardiac muscle: contraction of the heart ● Nervous tissue: senses stimuli and transmits signals throughout animal ○ neurons: nerve cells, transmit nerve impulses ○ glial cells/glia: help nourish, insulate, and replenish neurons 3. Define thermoregulation and explain how endotherms and ectotherms manage their heat budgets; explain the difference between the source and stability of body temperature define the terms involved ● Thermoregulation: main process where animals maintain internal temperature within a tolerable range ○ stability of body temperature ● Endothermic animals: generate heat by metabolism (birds and mammals) ○ active at a greater range of external temperatures ○ more energetically expensive ● Ectothermic animals: gain heat from external sources (most invertebrates, fishes, amphibians, nonavian reptiles) ○ tolerate greater variation in internal temperature ● poikilotherm: body temperature varies with environment ● homeotherm: relatively constant body temperature ● Exchange heat by radiation, evaporation, conduction, and convection ● General adaptations that help animals thermoregulate ○ insulation: provides blanket of dead air space ■ skin, feathers, fur, blubber, and trichomes reduce heat flow between organism and environment ○ circulatory adaptations: regulation of blood flow near body surface significantly affects thermoregulation ■ endotherms and some ectotherms can change amount of blood flowing between body core and skin ■ vasodilation: blood flow in the skin increases, facilitating heat loss ■ vasoconstriction: blood flow in skin decreases, lowering heat loss ○ Cooling by evaporative heat loss ■ lose heat through evaporation of water in sweat (energetically costly) ■ sweating/bathing moistens skin and helps cool animal down ■ panting increases cooling effect in birds and mammals ○ Behavioral responses: ■ endotherms and ectotherms use behavioral responses to control body temperature ■ some invertebrates have postures that minimize/maximize absorption of solar heat ○ Adjusting Metabolic Heat Production: ■ regulate body temperature by adjusting rate of metabolic heat production (most endotherms) ■ heat production increased by muscle activity (moving/shivering) ■ some ectotherms can shiver 4. Describe how a countercurrent heat exchanger may function to retain heat within an animal body ● transfers heat between fluid flowing in opposite directions ● requires a large number of closely aligned vessels that exchange heat over a relatively long distance 5. Define and understand bioenergetics and biosynthesis ● Bioenergetics: overall flow and transformation of energy in an animal ○ determines how much food an animal needs and is related to size, activity, and environment ● Biosynthesis: includes body growth and repair, synthesis of storage material like fat, and production of gametes ○ remaining food molecules after needs of staying alive are met 6. Define metabolic rate and explain the conditions associated with it, how it can be determined for animals and what the effects of temperature, activity, etc. are upon it ● Metabolic rate: amount of energy an animal uses in a unit of time ○ determine amount of oxygen consumed or carbon dioxide produced ○ Basal metabolic rate (BMR): metabolic rate of endotherm at rest at a comfortable temperature ○ Standard metabolic rate (SMR): metabolic rate of an ectotherm at rest at a specific temperature ○ ectotherms have lower metabolic rates than endotherms HORMONES: 1. Distinguish between the following pairs of terms: Hormones and local regulators; paracrine and autocrine signals ● Hormones: substances produced in one area of the body that affect another area of the body (chemical messengers) ○ chemical signals that are secreted into the circulatory system and communicate regulatory messages within the body ○ only target cells can respond ○ mediate responses to environmental stimuli and regulate growth, development, and reproduction ● Local regulators: not made in specialized glands like hormones and affect nearby cells by diffusion ○ paracrine: signals that act on cells near the secreting cell ○ autocrine: signals that act on the secreting cell itself 2. Describe the difference between steroid hormones having intracellular receptors and watersoluble hormones having cellsurface receptors ● Steroid hormones: can easily pass through cell membranes and is usually a change in gene expression ○ enter target cells and bind to protein receptors in cytoplasm or nucleus ○ then regulates transcription of specific genes in nucleus ● Watersoluble hormones: hormone binds to receptor and initiates a signal transduction pathway leading to responses in cytoplasm, enzyme activation, or change in gene expression 3. Explain how the antagonistic hormones insulin and glucagon regulate carbohydrate metabolism ● alpha cells produce glucagon and beta cells produce insulin ● antagonistic hormones that function in different ways ● Insulin reduces blood glucose levels ○ beta cells of pancreas release insulin into the blood ○ promotes cellular uptake of glucose ○ slows down glycogen breakdown in liver ○ promotes fat storage ● Glucagon increases blood glucose levels ○ alpha cells of pancreas release glucagon ○ liver breaks down glycogen and releases glucose ○ stimulates breakdown of fat and protein into glucose 4. Explain how the hypothalamus and the pituitary glands interact and how they coordinated the endocrine system ● Hypothalamus receives information from the nervous system and initiates responses through the endocrine system ● pituitary gland is attached to the hypothalamus and has a posterior and anterior pituitary ○ Posterior pituitary: releases antidiuretic hormone and oxytocin ■ acts directly on nonendocrine tissues ○ Anterior pituitary hormones: hormone production controlled by releasing and inhibiting hormones from the hypothalamus 5. Explain how the role of tropic hormones in coordinating endocrine signaling throughout the body ● Tropic hormone: regulates function of endocrine cells or glands ○ Thyroidstimulating hormone (TSH) ○ Folliclestimulating hormone (FSH) ○ Luteinizing hormone (LH) ○ Adrenocorticotropic hormone (ACTH) ● Endocrine signaling regulates metabolism, homeostasis, development, and behavior ○ Thyroid hormone: control of metabolism and development ○ Parathyroid hormone & vitamin D: control of blood calcium ○ Adrenal Hormone: response to stress ○ Steroid hormones: from adrenal cortex ○ Gonadal Sex Steroids NERVES AND THE NERVOUS SYSTEM 1. Distinguish among the following sets of terms: sensory neurons, interneurons, and motor neurons; membrane potential and resting potential; ungated and gated ion channels; electrical synapse and chemical synapse ● sensory neurons: where sensors transmit information along ● interneurons: integrates the information sent to the brain or ganglia ● Motor neurons: how the motor output leaves the brain or ganglia; triggers muscle or gland activity ● Resting potential: ○ neurons have semipermeable membranes that have active transport systems for some ions ○ has ion gates: membrane proteins that open or close to change permeability to a certain ion ○ resting neuron has a slight excess of negative charge inside ○ resting potential system has equal number of positive and negative ions ● Electrical synapses: electrical current flows from one neuron to another ● Chemical synapses: chemical neurotransmitter carries information across the synaptic cleft 2. Explain the role of the sodiumpotassium pump in maintaining the resting potential ● pumps K+ in and Na+ out ● 10 times more Na+ outside than inside and 2030 times more K+ inside than outside ● membrane is permeable to K+ but less to Na+ ● more K+ diffuses out than Na+ diffuses in; making inside negative messages are transmitted as changes in membrane potential ● resting potential is the membrane potential of a neuron when it is not sending signals ● Negative on the inside and charges are kept separate when the neuron is resting; highly polarized 3. Describe the stages of an action potential; explain the role of voltagegated ion channels in this process ● When stimulus depolarizes the membrane, Na+ channels open, Na+ diffuses into the cell ○ movement of Na+ into the cell increases the depolarization and causes more Na+ channels to open ○ strong stimulus results in a big change in membrane voltage called action potential ■ action potential occurs if stimulus causes membrane voltage to cross a certain threshold ■ brief allornothing depolarization of neuron’s plasma membrane ■ signals that carry information along axons 4. Explain why the action potential cannot travel back toward the cell body ● during refractory period, membrane is not able to depolarize and Na+ channels are deactivated ○ signal can only go one way 5. Describe saltatory conduction ● Saltatory conduction: in myelinated axons; depolarization jumps between nodes of Ranvier (fast) ○ jumps instead of traveling the entire length of the nerve fiber 6. Explain how electrical signals cross synapses and the role of excitatory and inhibitory neurotransmitters ● Presynaptic neuron synthesizes and packages chemical neurotransmitters in synaptic vesicles found in terminal ○ action potential causes release of neurotransmitter ○ neurotransmitter diffuses across the synaptic cleft and is received by the postsynaptic cell ● Excitatory neurotransmitters: the release of neurotransmitter will cause a depolarization and the continuation of the signal onto the next nerve ● Inhibitory neurotransmitters: cause hyperpolarization such that the next nerve downstream is less able to carry an action potential; cancels out the excitatory neurotransmitters THE NERVOUS SYSTEM 1. Compare and Contrast the nervous system of: hydra, sea star, planarian, nematode, clam, squid, and vertebrate ● Cnidarians have neurons arranged as nerve nets (series of interconnected nerve cells) ● More complex animals have nerves (bundles of cells that consist of the axons of multiple neurons) ● Bilaterally symmetrical animals show cephalization (clustering of sensory organs at the front end of the body) ○ Simple cephalized animals (flatworms) have a central nervous system ○ Annelids and arthropods have segmentally arranged clusters of neurons called ganglia ○ Invertebrates have a ventral nerve cord ○ Vertebrates have a dorsal spinal cord 2. Distinguish between the following pairs of terms: central nervous system, peripheral nervous system ● Central Nervous System: in vertebrates, composed of the brain and spinal cord ○ nervous system’s command station ○ sensory input reaches CNS, determines what it means, and tells body parts what to do ● Peripheral Nervous System: composed of nerves and ganglia ○ transmits information to and from CNS and regulates movement and internal environment ○ afferent neurons transmit information away from CNS ○ Cranial nerves: start in brain and terminate in organs of the head and upper body ○ Spinal nerves: start in spinal cord and extend to parts of body below head ○ motor system carries signals to skeletal muscles and is voluntary ○ autonomic nervous system regulates internal environment involuntarily ● Spinal cord conveys information from brain to PNS and produces reflexes independently of the brain 3. Compare the three divisions of the autonomic nervous system ● Sympathetic division: fightorflight response ● Parasympathetic division: promotes a return to rest and digest ○ sympathetic and parasympathetic divisions have antagonistic effects on target organs ● Enteric division: controls activity of digestive tract, pancreas, and gallbladder 4. Understand how neurons code different messages with identical action potentials ● can send different messages by varying the number or frequency of action potentials ● at any one synapse, the messages are either excitatory or inhibitory 5. Understand the integration of excitatory and inhibitory inputs in a neuron ● neurons receive messages as generator potentials from many terminals ● messages are received at synapses on dendrites or soma ● generator potentials may be excitatory or inhibitory ● if enough excitatory potentials are generated for the membrane potential to raise above the necessary threshold, an action potential will occur and will selfpropagate down the axon to the target cells ○ all action potentials on a neuron are identical ● generator potentials affect membrane potential at axon hilock ● A lot of excitatory inputs depolarization = greater probability for action potential ○ cell undergoes dramatic electrical charge ● A lot of inhibitory inputs hyperpolarization = lower probability for action potential ○ change in cell membrane that makes it more negative ○ restricts action potential by increasing stimulus needed to move membrane potential to action potential thresHELP PLZ* ● mix of excitatory and inhibitory inputs produces and intermediate generator potential 6. Understand the differences between the types of neurons in the vertebrate nervous system; sensory and motor neurons, interneurons ● Brain and spinal cord have gray matter and white matter ○ Gray matter: has neuron cell bodies, dendrites, and unmyelinated axons ○ White matter: has bundles of myelinated axons 7. Understand the basic functions of the divisions of the brain ● Brainstem: coordinates and conducts information between brain centers ● Diencephalon: has many neuroendocrine tissues (hypothalamus, pituitary gland) ○ regulates homeostasis and basic survival behaviors (feeding, fighting, fleeing, and reproducing) ○ main input center for sensory information to the cerebrum ○ main output center for motor information leaving cerebrum ● Cerebellum: coordinates and error checks during motor, perceptual, and cognitive functions ○ involved in learning and remembering motor skills ● Cerebrum: largest and most complex part of the brain ○ right side: controls left side of body; vice versa ○ had primary sensory and association areas where information is integrated ○ controls voluntary movement and cognitive functions ○ primary area involved in language, speech, and learning MUSCLES AND LOCOMOTION: 1. Explain the general structure of the vertebrate muscles and describe the interaction between antagonistic pairs of muscles ● made of many muscle fibers and each fiber had a single plasma membrane and have multiple nuclei ○ fibers arranged in bundles and bundles arranges to make muscle ○ fiber is supplied with nerves by a motor neuron to cause contraction ○ each fiber has many myofibrils which have sarcomeres (unit that has dark and light band) ● Muscles generate force via contractions ● can only contract forcefully; cannot elongate forcefully ○ external force (stretching) must be applied for a muscle to elongate ● to make the force, muscles must attach to something (bone, tendon…) and use ATP ● antagonistic pairs: one that extends and one that flexes 2. Describe the interactions between actin and myosin and the sliding filament model of muscle contraction. Include the roles of Ca and ATP ● Contractility: due to contractile proteins: actin and myosin that use ATP to power forceful shortening ● Within the sarcomere: ○ Thick Filaments: many different myosin molecules lined up in staggered array ○ Thin Filaments: 2 strands of actin and regulatory protein wrapped around each other ○ 6 thin filaments surround 2 thick filament ● for muscle to contract, actin and myosin interact so actin can be pulled inward ○ the components don’t shorten, they overlap each other ● ActinMyosin cross bridges are formed so the actin is pulled inwards towards the Mline (thin dark line in the middle of H zone/middle of sacromere) ● ATP needed; process is gradual and number of attachments formed is dependent on how much the muscle is contracted 3. Explain how calcium and the troponin complex controls muscle contractions ● When we decide to move, calcium released from sarcoplasmic reticulum bind to troponin molecules, causing tropomyosin molecules to move ○ reveales myosin attachment sites on actin myofilaments ● single phosphate on myosin head is removed connecting on the attachment sites on the actin (formation is cross bridge) ● ADP is used for power stroke that lets myosin heads bring actin closer; after ATP attaches to myosin heads ○ triggers the release of the myosin heads from the actin sites; ATP breaks down to ADP + P (recovery stroke) ● Calcium still present the process continues and overlaps until the calcium returns to the sarcoplasmic reticulum 4. Know what limits muscle strength and how contractions are controlled (fine vs. coarse) ● Maximum contractile force directly related to crosssectional area of muscle ○ bigger crosssection = more muscle cells = more sarcomeres ● Length of muscle does not determine maximum force ● See # 3 for how contractions are controlled 5. List and describe the four muscle types found in vertebrate skeletal muscle ● Tonic Fibers: contract very slowly ○ postural muscles of amphibians, reptiles, and birds ● Slowtwitch: contract slowly and fatigue slowly ○ mammalian postural muscles ○ also for repetitive or sustained exercise (marathons; wolves) ● Fasttwitch oxidative: high energy and activate quickly ○ rapid repetitive motions (flight muscles) ○ lots of mitochondria for work over long periods ● Fasttwitch glycolytic: contract rapidly and fatigue quickly; largely anaerobic ○ no sustained activity (cheetah) 6. Understand and explain the differences in the “cost of transport” for different modes of locomotion in animals??? *HELP PLZ* ● Running ● Flying ● Swimming 7. Know the difference between skeletal, smooth, and cardiac muscle ● Smooth: mainly in visceral organs and vascular system ○ exerts pressure on contents of a space (gut) or operates are valve (vein) ○ not very differentiated: sheets of cells with contractile proteins ○ doesn’t have discrete synapses: neurotransmitter/hormone is released between smooth muscle cells ○ supplied with nerves by autonomic nervous system (sympathetic/parasympathetic); responds to hormonal stimuli ○ slow, graded contractions; resistant to fatigue ● Cardiac: specialized to maintain heartbeat ○ columns of cells connected with gap junctions (maintain/coordinate contractions) ○ natural contractile rhythm controlled by specialized cells that act as neurons ○ pacemakers: clusters of electrically active fibers that generate and coordinate heartbeat ○ responsive to load: extra filling means strong contraction ○ responds to neural and hormonal signals ○ large blood supply; a lot of mitochondria; resists fatigue NUTRITION AND DIGESTION: 1. Name the three nutritional needs that must be met by an animal’s diet ● Chemical energy: converted into ATP and powers processes in the body ● Need source of organic carbon and organic nitrogen in order to construct organic nitrogen in order to construct organic molecules 2. Describe the four classes of essential nutrients ● Essential amino acids: 20 amino acids, can synthesize about half ○ remaining ones must come from food ○ protein deficiency: diet with insufficient in essential amino acids ○ individuals who only eat plant proteins need to eat different combinations to get all needed amino acids ● Essential Fatty Acids: ○ can synthesize most fatty acids needed ○ certain unsaturated fatty acids must come from diet ○ deficiencies in fatty acids are rare ● Vitamins: organic molecules required in diet in small amounts ○ 13 vitamins essential to humans identified ○ 2 categories: fatsoluble and watersoluble ■ digested and absorbed different ways ● Minerals: simple inorganic nutrients, usually required in small amounts 3. Describe the four main stages of food processing ● ingestion: act of eating ○ suspension feeders: aquatic animals, sift small food particles from water ○ substrate feeders: live in or on food source ○ fluid feeders: suck nutrientrich fluid from living host ○ bulk feeders: eat large pieces of food ● digestion: breaking down food into molecules small enough to absorb ○ chemical digestion: enzymatic hydrolysis splits bonds within molecules ● absorption: uptake of nutrients by body cells ● elimination: passage of undigested material out of digestive compartment 4. Distinguish between a complete digestive tract and a gastrovascular cavity ● Intracellular digestion: food particles are engulfed by endocytosis and digested within food vacuoles ● Extracellular digestion: breakdown of food particles outside of cells ○ in compartments that are continuous with the outside of the animal’s body ○ Gastrovascular cavity: animals with simple body plans that function in both digestions and distribution of nutrients ○ more complex animals have a digestive tube with 2 openings: mouth and anus (complete digestive tract or alimentary canal) 5. Follow a meal through a mammalian digestive system (list functions of each compartment; know general categories of digestive enzymes; compare where major macromolecules are absorbed) ● has alimentary canal and accessory glands that secrete digestive juices through ducts ○ accessory glands: salivary glands, pancreas, liver, and gallbladder ● food is pushed along by peristalsis (rhythmic contractions of muscles in the wall of the canal) ● Sphincters: valves that regulate movement of material between compartments ● 1. in oral cavity, salivary glands deliver saliva to lubricate food ○ teeth chew food into smaller particles that are exposed to salivary amylase (released in mouth), starting breakdown of glucose polymers ● 2. tongue shapes food into bolus and helps swallowing ○ throat/pharynx: junction that opens to both esophagus and trachea (windpipe) which leads to the lungs ● 3. esophagus conducts food from the pharynx down to the stomach by peristalsis ○ swallowing causes epiglottis to block entry to trachea and food is guided by larynx (upper part of respiratory tract) ● 4. stomach stores food and secretes gastric juice, which converts a meal to acid chyme ● 5. gastric juice is made up of HCl and enzyme pepsin ● 6. Parietal cells secrete hydrogen and chloride ions separately ● 7. Chief cells secrete inactive pepsinogen, converted to pepsin when mixed with HCl in stomach 6. Describe different evolutionary adaptations of vertebrate digestive tracts and how they correlate with diet ● Teeth ○ mammals have varying dentition that is adapted to usual diet ○ vary in size, shape, and cutting surface ○ differences in number of different kinds of teeth (incisors, canines, premolars, and molars) in different species ● difference in length of specific parts of the GI tract ○ herbivores: longer gut than carnivores ■ gives them longer time needed to digest vegetation ○ small intestine and cecum change in size the most ○ cecum: responsible for housing bacteria that break down plant cell walls to increase efficiency of plant digestion ● mutualistic associations with symbiotic microorganisms ○ food that’s hard to digest moves to gut where bacteria digest cellulose ■ herbivore gets energy from fatty acids ■ bacteria gets carbohydrates gives off fatty acids as by product ○ hindgut fermenter: herbivore where symbiotic breakdown happens in cecum after gastric compartment ○ Ruminants (foregut fermenters): herbivores that have specialized foregut called rumen ■ has symbiotic gut bacteria to break down plant material before enters gastric part of digestive tract 7. Explain where and in what form energyrich molecules are stored in an animal’s body ● food energy balances the energy from metabolism, activity, and storage ● almost all of animal’s ATP generation is based on oxidation of energyrich molecules: carbohydrates, proteins, and fats ● animals store excess calories primarily as glycogen in liver and muscles ● energy secondarily stores as adipose, or fat cells ● when fewer calories are taken in than are expended, fuel is taken from storage and oxidized CIRCULATORY SYSTEM: ● Most gases move easily through membranes by diffusion (slow) ○ good for single celled and small animals ○ large animals build distributive systems for the transport of gas and other materials ● Distributive systems use convection through circulating blood to carry materials through the body ● Small or thin animal cells can exchange materials directly with surrounding medium ● most animals transport system connect organs of exchange with body cells ○ have internal transport systems circulating fluid ● GVC: simple animals have a body wall that is 2 cells thick and encloses GVC (diffusion possible) 1. Compare and contrast open and closed circulatory systems ● Both have 3 basic components: ○ circulatory fluid (blood or hemolymph) ○ set of tubes (blood vessels) ○ muscular pump (heart) ● Open Circulatory Systems: insects, arthropods, and most molluscs ○ blood bathes the organs directly ○ body fluid is called hemolymph ● Closed Circulatory Systems: ○ blood is confined to vessels and is distinct from interstitial fluid ○ more efficient at transporting fluids to tissues and cells 2. Compare and contrast the circulatory systems of fish, amphibians, nonbird reptiles, and mammals or birds ● Cardiovascular system: humans and other vertebrates closed circulatory system ○ 3 main types of blood vessels: ■ arteries: branch into arterioles and carry blood to capillaries (arterial system) ■ Capillaries: networks are called capillary beds; where sites of chemical exchange between blood and interstitial fluid ■ Venuoles: converge into veins and return blood from capillaries to heart (Venous system) ● Gas Exchange: deliver respiratory gases to tissues for cellular respiration; remove gases that are a byproduct of cellular respiration to respiratory surfaces for disposal
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