BIOD102/ BIOD102 Module 5 V2 – Essential Biology II (Portage Learning) 2026/2027 | Verified Q&A | 100% Correct Answers | A+

BIOD102/ BIOD102 Module 5 V2 – Essential Biology II (Portage Learning) 2026/2027 | Verified Q&A | 100% Correct Answers | A+ Q: What are the functional units of the nervous system? Answer neurons Q: Basic structure / function of the neuron - dendrites, cell body and axon. Answer Dendrites- receive impulses from the synapses of other Axon- place along which the message is sent. Long rope like object. Myelin Sheath- cover around the Axon, increases the speed of the message sent. Q: What happens during an "action potential"? Answer Sodium (Na) start out and then rushes in- depolarization- +30mV (Na channels close and K open at this point) Potassium (K) begins inside, once +30mV is reached, K gates open and it rushed out- repolariztion Q: Synapse - define; explain transmission of information through a chemical synapse? Answer Junction between two neurons Q: Neurotransmitters are stored in vesicles in the axon terminals of the______ cell membrane (axon terminal) Answer presynaptic Q: Receptors for neurotransmitters will be on the _______ membrane(another neuron, a muscle cell , a gland cell) Answer postsynaptic Q: The most abundant specific tissue type in the body? Answer skeletal muscle Q: What are the functions of the muscular system? Answer movement, posture, joint stability and heat production Q: Skeletal muscles (organs) have? Answer connective tissue, nervous tissue and muscle tissue Q: Skeletal muscle is how abundant? Answer 35 - 40% of body mass. Q: Skeletal muscle fibers contract due to signals sent directly to them by ______neurons. Answer motor Q: Skeletal muscle structure Answer muscle, bundles of fibers, fiber, myofibril, sacromere, myosin, actin Q: What is the functional unit of the muscle system? Answer the sarcomere Q: Actin and myosin are: Answer myofilaments (intracellular filaments) Q: What explains how a sarcomere shortens? Answer Sliding Filament Theory Q: Do actin and/or myosin contract? Answer No Q: Does the actin "slide" OR does the myosin "slide"? Answer Actin (thin filaments) Q: True or False. During muscle contraction, the muscle, the fiber, the myofibrils, the sarcomere shorten but the myofilaments (actin and myosin) don't change in length. Answer False Q: Motor unit Answer one motor neuron and all fibers it controls Q: Which would have the ability to control fine movements - a large motor unit or a small motor unit? Answer small motor unit Q: Which would have greater strength - a large motor unit or a small motor unit? Answer large motor unit Q: Two muscles (#1 and #2) have the same number of fibers (2000) but muscle #1 is innervated by 100 motor neurons and muscle #2 is innervated by 20 motor neurons. Assume that motor unit size doesn't vary much within each muscle. Which muscle (#1 or #2) is "wired" for stronger contractions? Answer Muscle 2 Q: Explain why a skeletal muscle cell's membrane has "tubules" which go deep into the cytoplasm of the cell. Answer To conduct impulses from the surface of the cell to the interior Q: Skeletal muscle cell specializations include Answer 1) T tubules 2) myfibrils, myofilaments and sarcomeres 3) an elaborate endoplasmic reticulum for storage of calcium ions 4) multinucleated 5) contains lots of mitochondria 6) very long and thin 7) excitable cells Q: Muscle cell contraction: Number the following in the order that they occur. (#1 first - #5 last)-calcium ions (Ca++) are released from endoplasmic reticulum-acetylcholine released "power strokes" occur & sarcomere shortens-a wave of action potentials reach the end of a motor neuron axon-muscle cell excites Answer 1. a wave of action potentials reach the end of a motor neuron axon 2. acetylcholine released 3. muscle cell excites 4. calcium ions (Ca++) are released from endoplasmic reticulum 5. "power strokes" occur & sarcomere shortens Q: The site where a motor neuron communicates with a muscle fiber called the neuromuscular junction is Answer a synapse Q: __________________ is the neurotransmitter released at the neuromuscular junction. Answer Acetylcholine Q: What allows myosin to bind to actin? Answer Calcium ions Q: ATP is required for muscle contraction. Explain the change(s) that occur in the sarcomere when ATP is used. Answer I-band becomes narrower; Z-lines move closer together (sarcomere shortens);H-zone becomes narrower Q: ATP is ALSO required for muscle relaxation. Explain why. Answer To enable the muscle to contract again Q: Is ATP available after death? Answer No Q: Are the motor neurons firing after death? Answer Yes Q: Why is Ca++ coming out of storage in rigor mortis? Answer Calcium is released into the cytosol due to the deterioration of the sarcoplasmic reticulum. Q: Why do the skeletal muscles contract and not relax after death? Answer Because no ATP is available for the muscles to relax Q: True or False. Muscle cells are excitable cells. Answer True True or False. Muscle cells and neurons are the only cells within the body that are "excitable". Answer True List 6 major endocrine glands (You may list both sex organs) Answer Pituitary gland, thyroid gland, adrenal glands, pancreas, testes, and ovaries Are the major endocrine glands the only locations within the body where hormones are produced? Answer No, the brain, liver, thymus, heart, intestine, stomach, skin, kidneys, placenta all release hormones, but they may not be considered as endocrine glands. An ____________ gland is a ductless gland that produces hormone(s). Endocrine _________ glands have ducts and releases fluid to specific locations in the body by way of the ducts. Exocrine True or False. All hormones are transported throughout the body by the bloodstream (circulatory system). True The cell type that responds to a hormone is called a ____________cell. target What does a cell have to have in order to respond to a particular hormone? Receptor The two major types of hormones are: peptide/protein hormones and steroid hormones. Which type of hormone (peptide or steroid) requires membrane receptors (on surface)? Peptide hormones Which type of hormone (peptide or steroid) requires cytoplasmic receptors (internal)? Steroid hormones Steroid hormones can __________ but peptide/protein hormones cannot diffuse through the membrane Rapid cellular responses are more likely with ___________ type hormones than with __________ type hormones. Peptide; Steroid This area of the brain also produces ADH and Oxytocin (neurohormones) that are released at the posterior pituitary gland. Hypothalamus Which area of the brain controls the anterior pituitary gland? Hypothalamus Hypothalamus produces: Inhibiting and Releasing Hormones What are the target cells for Inhibiting and Releasing hormones? target endocrine cells in the anterior pituitary True or False. The anterior pituitary produces many different hormones, some of which target other endocrine glands (sex organs, adrenal cortex, thyroid) and, therefore, the anterior pituitary is called the "master gland" of the endocrine system. True The posterior pituitary does NOT produce_________? hormones Which 2 hormones are released at the posterior pituitary? ADH and Oxytocin Are ADH and Oxytocin hormones neurohormones? yes ADH (antidiuretic hormone) targets cells within the ________? kidneys Oxytocin targets smooth muscle cells within the ___________? breasts and uterus Thyroid hormone targets _________ and increases _________? most all cells within the body, metabolism When there is plenty of thyroid hormone in the bloodstream, the hypothalamus ______ (does or does not) produce TRH. does not: negative feedback When there is plenty of thyroid hormone in the bloodstream, the anterior pituitary ____ (does or does not) produce TSH. does not, negative feedback In summary, when there is plenty of thyroid hormone in the bloodstream a ________ (positive or negative) feedback occurs that influences the release of TRH and TSH. negative Hyperthyroidism high metabolic rates, thin, always warm, etc. Hypothyroidism low metabolic rates, can have problems with weight gain, always cold, lethargic. Graves Disease autoimmune disorder where antibodies bind to the receptors for TSH found on the thyroid gland. A goiter is: swollen thyroid gland Goiters can occur with either hyperthyroidism or with hypothyroidism. Why does lack of iodine in the diet cause goiters? A low amount of thyroxine in the blood, due to lack of dietary iodine to make it, gives rise to high levels of TSH, which stimulates the thyroid gland to increase many biochemical processes Which hormone causes blood calcium levels to drop? calcitonin Which gland produces calcitonin? thyroid What are the target cells of calcitonin? bones, kidneys and gut Which hormone causes blood calcium levels to rise? parathyroid hormone Which gland produces the parathyroid hormone? parathyroid gland What are the target cells of parathyroid? Bones, Kidneys, and Gut Insulin is produced by: beta cells of pancreas Insulin causes blood glucose levels to: decrease Insulin targets: most cells of the body Glucagon is produced by: alpha cells of pancreas Glucagon causes blood glucose levels to increase Glucagon targets liver, fat, and muscle cells (areas where food had been stored as glycogen, fat or proteins) In Type I diabetes, the immune system is attacking _______ (alpha or beta) cells. beta Autoimmunity loss of function of normal tissues within the body due to an inappropriate immune response Is the pancreas controlled by the anterior pituitary? No. It is its own control What are some of the effects on the body of high blood sugar? damages capillaries and arteries Where are adrenal glands found? on top of each kidney Adrenal gland structure: Cortex (outside) and medulla (inside) Cortex produces: Corticosteriods (e.g. cortisol) Medulla produces: catecholamines (e.g. epinephrine) Which part (cortex or medulla) is critical for long term responses to stress? adrenal cortex Which part (cortex or medulla) is critical for short term responses to stress? medulla Which part (cortex or medulla) is controlled by the anterior pituitary gland secretions? cortex The hypothalamus controls the anterior pituitary's production of: LH and FSH which are hormones that target cells within the sex organs. LH and FSH influence: gamete (egg and sperm) production and sex hormone (testosterone, or estrogen and progesterone) production by the gonads Sex Hormones: Testosterone and Estrogen and Progesterone (steroid hormones) The sex hormones stimulate gamete production by the gonads and cause: secondary sex characteristics Which hormone is produced only by an implanted embryo? Human Chorionic Gonadotropin Ovulation (release of an egg) occurs when levels of ____________ (LH or FSH or Estrogen or Progesterone) " spike". estrogen Growth hormone is produced by the anterior pituitary gland The concept of "biosphere" refers to the fact that life has changed in response to the earth, but the earth has not changed in response to life. False Cells A. Are driven by a complex biochemistry b. eat, grow and reproduce c. can exist singly or as part of multicellular organisms d. come from replication of previous cells The basic idea driving most research on the origin of life is that compared to modern biochemistry, the early precursors of life must have been chemically simpler Even in an exergonic reaction, the reactants must be __________ in energy state in order to transform into the products, which are at a _________ energy state. raised, lower Each step in the biochemical pathways regulating living organisms today are regulated by protein catalysts called __________. enzymes Catalysts serve to _______ the rate of chemical reactions by ________ the activation energy. increase, lowering Autocatalysts are a special class of catalysts that promote reactions that create more ________. autocatalyst Autocatalysts, like living organisms, have a remarkable type of growth called exponential If an animal population doubles in size every 10 years, how big will it become after 50 years if it starts at 100? (so, starting now at 100, in ten years it's how much? In 20? etc.) 3,200 Conditions on the early earth surface are thought to include ________ ultra violet light and ________ carbon dioxide than today. higher, higher Photosynthesis yields __________, respiration yields ___________ and DNA expression yields _____________ sugar, energy, proteins The component of today's living systems that exhibit "autocatalytic" capacity is whole organisms Major transitions in the history of life include, in order of appearance, prokaryotic cells, eukaryotic cells, multicellular organisms The earliest rocks dated so far formed 3.8 billion years ago (BYA), and the earliest rocks with fossil bacteria formed _______ BYA. 3.5 By 2.7 billion years ago, rocks formed that contained ____________ indicating that well before that life existed that could ___________. iron oxide, photosynthesize At Hakalau Forest in ________, ranchland is being restored to forest, invasive plants are being removed, and native ones are being planted, and native birds are being protected while new populations of them are being established. Hawaii In order for two organisms to belong to the same species, individuals of their species must __________. be able to reproduce and have fertile offspring ___________ is the only process that can change a gene's DNA and therefore give rise to new variations of the gene. Mutation Which of the following is an example of selective breeding (artificial selection) by humans? the diversity of dog breeds in the world today Heavy rains and mudslides cause a river to change course, isolating two groups of lizards of the same species from one another. Over a long period of time ________. the groups will possibly diverge genetically, and speciation may occur Which statement below most accurately describes a phylogenetic tree? A phylogenetic tree is a branching diagram used to illustrate a scientist's hypothesis about how divergence took place among evolutionary lines. Which of the following populations would be most vulnerable to extinction? a small, endemic population Most extinction ________. generally occurs when species cannot adapt genetically to changes in environmental conditions Which of the following is true? Species on Earth today are but a fraction of all species that ever lived. A __________ is defined as the living and nonliving elements in the area around an organism. habitat An ecosystem ________. encompasses all the organisms and the physical and chemical environment within an area A coyote, which can alter its food intake to match seasonal abundance of plants, fruits, or small animals, is considered to be ________. a generalist, able to be flexible in major dimensions of its niche The passenger pigeon is __________. extinct Territoriality generally results in what kind of population distribution? uniform A population's age structure generally ________. indicates the relative numbers of individuals of different ages within a population If we ignore the effects of migration when determining population growth rates, we would calculate the population's __________, which equals __________. rate of natural increase; (birth rate) - (death rate) Populations lacking any environmental resistance tend to increase by ________. exponential growth The carrying capacity is the ________. maximum sustainable population size that a given environment can support Density-dependent factors ________. include the effects of disease, predators, and food on a single species within a community Which of the following is accurate? Ecotourism combines wildlife conservation with economic benefits. Describe the evolutionary relationships between following clades: Metazoa, Eumetazoa, Bilateria, Protostomia, Deuterostomia, Spiralia, Ecdysozoa -all animals belong to metazoa -all animals with true tissues belong to eumetazoa -all animals with bilateral symmetry belong to bilateria -bilateria diverged into protostomia and deuterostomia -protostomia diverged into spiralia and ecdysozoa What characteristic do all animals belonging to Eumetazoa possess? true tissues What type of symmetry do all animals belonging to Bilateria possess? Are animals in Bilateria diploblastic or triploblastic? Name the germ layers that animals in Bilateria develop from. What are the two major lineages of Bilateria? Protostomia and deuterostomia What are the two lineages of Protostomes called? Give one characteristic shared by the animals in each of these two clades. -Spiralia and Ecdyosoza -In protostomia, blastopore becomes mouth Which of the animal phyla studied so far this semester belong to each of the following clades: Metazoa, Eumetazoa, Bilateria, Protostomia, Spiralia, Ecdysozoa? Metazoa: porifera Eumetazoa: cnidaria Bilateria, Protostomia, Spiralia: platyhelminthes Bilateria, Protostomia, Ecdysozoa: nematodes A body cavity is... an internal space that is closed to the outside Explain the difference between acoelomate and blastocoelomate aceolomate has no body cavity, blastocoelomate has body cavity Match the word that describes the type of body cavity each animal has: Flatworm (acoelomate, blastocoelomate, true coelomate) Roundworm (acoelomate, blastocoelomate, true coelomate) -Flatworm: acoelomate -Roundworm: blastocoelomate What is the cuticle and what is its functions? -Layer of cells, composed primarily of collagens, that is secreted by and covers epidermis -Functions: protection, helps maintain shape, and serves as antagonist to longitudinal muscles Explain what ecdysis is The shedding of the cuticle Body plan: symmetry, how many tissue layers, are nematodes cephalized -Bilateral symmetry, triploblastic, cephalized What types of muscles do they have? Explain how muscles, blastocoelom, and cuticle work together as a hydrostatic skeleton for movement. -Nematodes only have longitudinal muscles -cuticle serves as antagonist to longitudinal muscles, giving shape, and blastocoelom has higher than normal hydrostatic pressure Do Nematodes have an incomplete or complete digestive tract? complete digestive tract How do they ingest food, where is it chemically digested, where are digested nutrients absorbed? -many methods of ingestion, food enters through mouth (pharynx), then into intestines where chemical digestion happens -cross over wall of intestine into blastocoelom how are digested nutrients distributed to the rest of the body, how does indigestible material leave the body? -blastocoelom serves as a simple circulatory system that distributes nutrients to all parts of body -undigested material leaves through anus, nitrogenous waste diffuses across body wall Why can't the roundworm use contractions of the intestine to move food through its digestive tract? It does not have muscles surrounding the digestive tract. Instead, the force of the pumping pharynx and movement of whole body moves food through intestines Where does gas exchange occur in nematodes? Occurs by diffusion across surface of body and enters blastocoelem where gases are distributed Learn More You can also click on terms or definitions to blur or reveal them