Final Exam Bio

Question 1

Identify the characteristics that generally distinguish animals from other types of organisms.

Answer 1

All animals are eukaryotic, multicellular organisms, and almost all animals have specialized tissues, all are motile, all are heterotrophic (ingesting living or dead matter), most animals reproduce sexually and the offspring pass through a series of developmental stages that establish a determined body plan (the shape of an animal)

Question 2

Distinguish between radial symmetry and bilateral symmetry.

Answer 2

Radial Symmetry - has a longitudinal (up-and-down) orientation. Ex. sea anemone
Bilateral Symmetry - have upper (dorsal) and lower
(ventral) surfaces, plus distinct front (anterior) and back (posterior) ends. Ex. the goat

Question 3

Identify the three germ layers (endoderm, mesoderm, and ectoderm) that form the tissue types found in most animals, and learn about some of the tissues that come from each germ layer.

Answer 3

Endoderm - The inner layer (innermost lining of internal organs, such as those in the digestive tract, the liver, the pancreas, and the lining of the lungs)
Mesoderm - Middle layer (The majority of organs and tissues in an adult animal, such as the kidney, heart, muscles, blood vessels, bones and the dermis (inner layer of skin) develop from the mesoderm.)
Ectoderm - Outer layer, the lens and cornea of the eye,
and the nervous system (brain and nerves).
Animals with Radial Symmetry have Endoderm and Ectoderm.
Animals with Bilateral Symmetry have Endoderm, Ectoderm, and Mesoderm

Question 4

Define the different types of body cavities (pseudocoelom and coelom) and identify the advantages that animals with body cavities have compared to animals without body cavities (acoelomate).

Answer 4

Pseudocoelom - Has a fluid-filled space between the endoderm and ectoderm, but mesoderm only lines the ectoderm side of the space and does not cover the organs.
Coelom - A Fluid-filled space exists between the endoderm and ectoderm that is completely lined with mesoderm.
Advantages that animals with body cavities have compared to animals without body cavities (acoelomate) - Advanced organ development, better movement, cushioning and support for organ protection, circulatory system can be well-developed, are larger and more complex.

Question 5

Define segmentation and cephalization, and identify the advantages of these features.

Answer 5

Segmentation - Division of an animal into repeating body parts. Allows for greater flexibility and mobility, repeating units allow for specialization of specific body parts like development of legs, arms, and wings.
Cephalization - A concentration of sensory organs in the head region. Placement of sensory organs around mouth of a heterotroph allows it to be efficient at finding food, more efficient at detecting potential predators and not becoming food.

Question 6

Identify the four types of animal tissues, and some of the functions which each performs.

Answer 6

Epithelial - protection, secretion, absorption, excretion, filtration, diffusion, and sensory reception.
Connective - Provides support, protection, and structure.
Muscle - Contracts to move, pump blood, move materials. Ex. Skeletal, cardiac, and smooth muscles
Nervous - coordinates many bodily functions in response to stimuli. Ex. neurons

Question 7

Define tissues, organs and organ systems, and examine the relationships between these.

Answer 7

Tissues - Groups of similar cells carrying out a specific related function. Tissues combine to form organs.
Organs - Made up of many different tissues working together to carry out a specific function. Organs form organ systems.
Organ System - come together to create an entire organism. Form an organism.

Question 8

Define homeostasis, negative feedback, and positive feedback, and be able to describe the relationship of both feedback mechanisms to homeostasis.

Answer 8

Homeostasis - Maintenance of the body within a certain range, is maintained by negative feedback loops.
Negative Feedback - Anything that causes a response of the body to reverse. Level to high in body then its reversed to low and vice versa.
Positive Feedback - Maintains the direction of the stimulus, possibly accelerating it.

Question 9

Examine a variety of animals, identify similarities and differences among animals, and use this information to gain a better understanding of animal phylogeny.

Answer 9

All animals have a few things in common. They are multicellular, eukaryotic, heterotrophic, embryonic development, maintain homeostasis, and most reproduce sexually.
Many animals are symmetrical and evolutionary trends from radial to bilateral.
Evolutionary trends have seen more cephalized animals.
Some animals are on the tissue level with two germ layers and some animals are organ level with 3 germ layers.
Not all animals are segmented, but many are.

Question 10

Identify the molecules necessary for and produced by aerobic respiration in animal cells, and how these materials are acquired and transported within a multicellular organism.

Answer 10

Molecules necessary for aerobic respiration are oxygen and carbohydrates.
Carbohydrates are acquired by the digestive system in the breakdown of food, oxygen is acquired by the respiratory system, and both transported to and from cells by the circulatory system.
All three systems work together to get materials where they need to be for cellular respiration.

Question 11

Define incomplete and complete digestive systems, and identify the overall tasks of a complete digestive system.

Answer 11

Incomplete digestive systems have one opening into a single organ where digestion and absorption occur. They are less complex.

Complete digestion has 2 openings and a one way transport of materials.
Task is to ingest materials, digest them into smaller molecules, and to absorb those molecules into the blood stream so they can be carried to cells throughout the body.

Question 12

Identify the major components of the mammalian digestive system, understand the functions of each organ, and how these organs interact to accomplish the overall tasks you learned in objective 2.

Answer 12

The mouth and salivary glands start the breakdown of carbs.
The esophagus takes the food from the mouth to the stomach by peristalsis.
The liver secretes bile into the gallbladder and removes toxins from the blood.
The pancreas secretes digestive enzymes to break down molecules.
The stomach produces acid and breaks down food mechanically.
The SI continues enzymatic digestion.
Nutrients are absorbed in the SI.
The LI absorbs water, vitamins, ions and waste is eliminated.

Question 13

Identify the biochemical and cellular processes involved in digestion and absorption in the mammalian digestive system.

Answer 13

Biochemical - does the digestion/breaks down large food
Cellular processes - absorb the nutrients

Question 14

Understand the process of fat digestion (including the function of bile and lipase), and use the results from an experiment to better understand the other processes involved in digestion (objective 4).

Answer 14

Digested by lipase and bile emulsifies the fats into smaller molecules to be digested into glycerol and fatty acids.
They are digested in the small intestine.
With the presence of bile, the rate of fat digestion was higher.
Fats are digested into the circulatory system.
They are then packed and exported to lymph vessels for transport.

Question 15

Define vitamins and minerals, learn the different types, and why these are important for maintaining homeostasis.

Answer 15

Vitamins and minerals are elements acquired by our diets that we can’t live without.
Too much or too little of them can cause problems.
There are two types of vitamins. Water soluble and fat soluble.
Vitamins play an important role in metabolism, immunity, and digestion.
Minerals help the body grow and stay healthy.
They also play a role in body functions from building bones to transmitting nerve signals.
Vitamins are organic molecules because they contain carbon.
Minerals are inorganic because they lack the element carbon.

Question 16

Identify some structural adaptations that allow different animals to exploit different diets.

Answer 16

Some animals have symbiotic protozoa or bacteria to aid digestion of cellulose and pectin.
They can house a number of cellulose digesting bacteria.
Some are ruminant and have 4 stomachs and a longer small intestine.
Birds have a two part stomach, a glandular portion known as the proventriculus and a muscular portion known as the gizzard.
The gizzard performs the same function as mammalian teeth, grinding and disassembling the food, making it easier for the digestive enzymes to break down the food.

Question 17

Understand various adaptations of animals for gas exchange (acquisition of O2 and release of CO2) with the environment and why gas exchange is necessary.

Answer 17

Aquatic animals have gills to help in gas exchange. Blood and water flow in opposite directions over the lamellae.
Branching trachea can help in the dispersion of gases and the evolution of lungs for animals was also important for sites of gas exchange. Gases move by diffusion within the tracheal system. The gases are moved around by body movements, there is no blood to circulate. This is found in insects.
In mammals gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs.
Gas exchange is necessary for organisms because o2 is needed for cellular respiration to occur and the product co2 is a waste product that needs to be transported out of the cells and out of the organism.

Question 18

Describe the relationship between breathing and cellular respiration.

Answer 18

Breathing allows for the intake of o2 and the release of c02 for cellular respiration.
Inhalation brings in o2 and the o2 is absorbed into the bloodstream and taken to cells so that they can use the o2 as a reactant in cellular respiration.
The co2 that is produced is taken out of the cells and transported to the lungs where it diffuses out of the blood stream and is exhaled for the release of the co2 waste product.

Question 19

Describe the relationship and interaction between the mammalian circulatory system and respiratory system. Understand how gases are carried by components of the blood, and how gases are transferred to and from tissues.

Answer 19

The oxygen that is breathed in diffuses into the bloodstream in the lungs.
The oxygenated blood is pumped through the heart and to the rest of the body in the circulatory system.
In mammals, the rbc’s carry the oxygen bound to hemoglobin molecules through the circulatory system to cells.
The co2 is taken back in the deoxygenated blood through the circulatory system into the lungs (bicarbonate is converted back into co2 in the lungs) where it diffuses out of the blood stream and exhaled out.

Question 20

Describe open and closed circulatory systems and explain the advantages and disadvantages of each type.

Answer 20

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.
An open circulatory system describes a system where blood and interstitial fluid are allowed to mix in an organism.
Open systems are less complex and require less energy.
Closed have higher blood pressure amd are more efficient.

Question 21

Describe the characteristics of the various circulatory systems found in vertebrates; discuss these in terms of the evolution of the circulatory system in animals.

Answer 21

Some animals have 2 heart chambers, 3 heart chambers, or 4 heart chambers.
In three heart chambers, the oxygenated and deoxygenated blood is temporarily mixed but in 4 heart chambers, there are completely separate circuits for pulmonary and systemic systems.
The circulatory system with four heart chambers is more efficient and allows for organisms to grow larger.

Question 22

Identify the major components of the vertebrate cardiovascular system, including arteries, veins, and capillaries, and understand the basic functions of this organ system as well as the function of each component.

Answer 22

The arteries take oxygenated blood from the heart to the rest of the body.
Arteries are thick walled and do not contain valves.
The pulmonary artery is the only artery that carries deoxygenated blood.
The veins take the deoxygenated blood from the body to the heart.
Veins are thin walled and have valves to keep the flow of blood unidirectional in the presence of gravity.
The pulmonary vein is the only vein that takes oxygenated blood to the heart.
The capillaries are single cell thick vessels in between arteries and veins where nutrient and gas exchange occur.
The function of this system is to transport oxygen and materials/nutrients throughout the body.

Question 23

Trace the flow of blood into, through, and out of the mammalian heart, naming the major structures of the heart in the order blood travels through them.

Answer 23

Unoxygenated blood from the body returns to the heart via the vena cava.
Unoxygenated blood enters the right atrium. Unoxygenated blood enters right ventricle.
Oxygenated blood pumped to lungs via pulmonary artery.
Gas diffusion within the lungs.
Oxygenated blood leaves lungs via pulmonary vein.
Oxygenated blood enters left atrium. Oxygenated blood enters left ventricle.
Oxygenated blood pumped out to body via aorta.

Question 24

State the functions of the various components of blood, distinguishing among erythrocytes (red blood cells), leukocytes (white blood cells), and thrombocytes (platelets).

Answer 24

Red blood cells carry oxygen bound to hemoglobin throughout the body.
White blood cells are part of the immune system and help fight foreign invaders in the body.
Platelets help form blood clots when there is a scrape so that the bleeding stops.
Platelets are much smaller and white blood cells are fairly big.

Question 25

Identify the subdivisions of the human nervous system (central and peripheral) and describe their composition and functions.

Answer 25

The CNS contains the Brain and the Spinal Cord (interneurons). It is responsible to making decisions from incoming information and sending a signal out to respond. The PNS is made of the sensory and motor neurons. They carry info to the CNS from the stimulus and carry messages from the CNS to muscles, glands, organs, and other structures for the response. Can be voluntary or involuntary.

Question 26

Identify and describe the functions of the different types of neurons (sensory neuron, motor neuron, and interneuron), and where each type is found in the human nervous system.

Answer 26

Sensory neurons (PNS) carry impulses from receptors to the CNS. Interneurons (CNS) filter and process incoming infor and formulate responses. Motor neurons (PNS) carry impulses away from CNS.

Question 27

Identify and describe the functions of the different parts of a typical neuron (cell body, axon, and dendrites) and the synapse between neurons.

Answer 27

The dendrites of the neuron carry signals toward the cell body. The cell body makes a decision from the signals and sends it to the axon where the signal is sent away from the cell body to the synapse where neurotransmitters are used to continue the signal to other neurons or to inhibit the continuation of the signal.

Question 28

Understand the molecular basis for the resting potential of a nerve cell, and how this potential changes during the initiation and propagation of a signal in that cell.

Answer 28

In a resting neuron it has a resting potential of -70 mv. The action potential is an explosion of electrical activity that is created by a depolarizing current. This means that some event (a stimulus) causes the resting potential to move toward 0 mV. When the depolarization reaches about -55 mV a neuron will fire an action potential. This is the threshold. If the neuron does not reach this critical threshold level, then no action potential will fire. A stimulus first causes sodium channels to open. Because there are many more sodium ions on the outside, and the inside of the neuron is negative relative to the outside, sodium ions rush into the neuron. It takes longer for potassium channels to open. When they do open, potassium rushes out of the cell, reversing the depolarization. Also at about this time, sodium channels start to close. This causes the action potential to go back toward -70 mV (a repolarization). The action potential actually goes past -70 mV (a hyperpolarization) because the potassium channels stay open a bit too long. Gradually, the ion concentrations go back to resting levels and the cell returns to -70 mV.

Question 29

Describe how signals are conducted along axons (action potential) and between nerves (synaptic transmission), and understand the feedback mechanisms involved in signal conduction by the nervous system.

Answer 29

Signals are conducted along axons by action potentials and the movement of K+ and Na+. Na+ rushes inside the cell and K+ rushes out and increases the potential mv. Once the cell reaches its threshold, an AP occurs, and then during repolarization, K+comes back in and Na+ goes back out to get it back to its resting potential. The sodium potassium pump moves extra ions after repolarization to maintain resting potential. In between nerves in the synapses neurotransmitters are used to continue the signal to other neurons or to inhibit the continuation of the signal. This is controlled by the positive feedback of sodium rushing into the cell to continue the signal traveling down the axon.

Question 30

Define neurotransmitter and hormone, how these molecules influence mammalian organs and tissues, and where the receptors for these molecules are located.

Answer 30

Neurotransmitter - chemical substance that is released at the end of a nerve fiber by the arrival of a nerve impulse and, by diffusing across the synapse, causes the transfer of the impulse to another nerve fiber, a muscle fiber, or some other structure. Receptors - the nerve cells where the signal is being propagated. Hormone - a regulatory substance produced in an organism and transported in tissue fluids such as blood or sap to stimulate specific cells or tissues into action. Receptors are specific target cells or tissues.

Question 31

Identify the functions of a selected set of human endocrine system components.

Answer 31

Anterior pituitary - FSH: works with Lh to insure proper function of gonads/ LH: works with FSH Posterior Pituitary - oxytocin: produced by hypo, secreted by p.p. functions during childbirth and lactation/ ADH: affects water balance through kidneys Thyroid - makes thyroid hormone that regulates metabolic rate and growth and development. Adrenal Gland - Epinephrine/adrenaline: prepare body for fight or flight / cortisol: produced response to stress Gonads - Testes - testosterone: male secondary sexual characteristics and sperm production/ Ovaries - estrogen: female secondary sexual characteristics and egg production/ progesterone: helps regulate menstrual cycle and maintain pregnancy Pancreas - insulin: reduce blood glucose/ glucagon: increase blood glucose

Question 32

Describe the regulation of blood sugar levels as an example of endocrine function and homeostasis, including an understanding of the functions of pancreatic hormones and their target tissues.

Answer 32

Blood sugar levels are regulated by hormones secreted by the pancreas. When blood sugar levels rise, insulin is released from the pancreas and targets body cells to take in glucose and lower glucose levels. When glucose levels are too low, the pancreas secretes glucagon and it targets the liver to release glucose into the bloodstream. This helps maintain homeostasis and maintaining a balanced sugar level in the bloodstream.

Question 33

Understand the relationship between the endocrine system and the reproductive system, including the functions of some endocrine hormones in males and in females.

Answer 33

The endocrine system controls the reproductive system. GnRH is released by the hypothalamus and triggers the pituitary gland to release LH and FSH. These hormones stimulate estrogen/progesterone in females and testosterone in males. Hormones in the endocrine system in the males control sperm production, puberty, and secondary sexual characteristics. In females, they control secondary sexual characteristics, ovulation, puberty, and oxytocin is responsible for contractions and lactation.

Question 34

Differentiate between asexual reproduction and sexual reproduction in animals, and learn about the advantages and disadvantages of each of these modes of reproduction.

Answer 34

Asexual reproduction allows for rapid growth and requires less energy, but it results in genetically identical offspring and only requires one parent. Sexual reproduction results in offspring who are adapted to the environment and less likely to become extinct. They are genetically unique and require two parents.

Question 35

Describe the regulation of digestion by the endocrine and nervous systems, and relate this to the concepts of homeostasis and negative feedback.

Answer 35

Digestion is regulated by endocrine and nervous system. Stimulus like seeing and smelling food triggers to autonomic nervous system to send messages to the stomach to start secreting substances to prepare for the food. The stretching of the stomach sensors signal nerves to order secretion of stomach juices and gastrin and stimulate muscle contractions. The gastrin feeds back into the bloodstream to increase production of stomach juices and stim muscle contractions. The stretching of the SI and presence of lipids and carbs. Nerves inhibit secretion of stomach juices and gastrin/ inhibits muscle contractions. Hormones stimulate release of bile and digestive enzymes and inhibit stomach secretion and muscle contraction.

Question 36

Understand how the human endocrine system functions and how this system relates to other organ systems.

Answer 36

The endocrine system is made up of glands that produce and secrete hormones, chemical substances produced in the body that regulate the activity of cells or organs. These hormones regulate the body's growth, metabolism (the physical and chemical processes of the body), and sexual development and function. This system relates to other organ systems because hormones have target cells or organs that control the function of those cells or organs.

Question 37

Describe the integumentary system and understand its general function.

Answer 37

The integumentary system defines us. It is composed of many tissues - the skin, nerves, hair cells, blood vessels, fat. The main functions are to protect the body from physical damage, invasion from other organisms, dehydration, overheating, and freezing. It has three layers, the epidermis (outermost layer, no blood vessels) the dermis ( thick middle layer of connective tissue and hair follicles, muscles, sweat glands, sensory neurons, and blood vessels) and the hypodermis (deep layer, mostly fat).

Question 38

Identify the five major human senses and classify them as chemoreceptor, photoreceptor, or mechanoreceptor systems.

Answer 38

Chemoreceptors - smell/taste : Mechanoreceptors - hearing/touch : photoreceptor - sight

Question 39

Identify the cellular components of a reflex arc, and the relationship of these structures to the function of the reflex arc.

Answer 39

A reflex arc is a short series of nerve cells consisting of a sensory neuron, and interneuron in the spinal cord and a motor neuron. The impulse goes to the spinal cord instead of the brain because it is a faster route and it gives a faster response than the time it would take the brain to process the information.

Question 40

Define immunity, and describe the differences between the adaptive (specific) and innate (non-specific) defense mechanisms that contribute to immunity.

Answer 40

Immunity is the ability of the body to defend itself against foreign cells or viruses and even abnormal body cells like cancer. Innate immunity is non specific and includes physical barriers, inflammation, protective proteins, cells that kill other cells, and fevers. Adaptive immunity is specific and defends against previously exposed invaders that the body has encountered. It contains T and B cells.

Question 41

Explain the main characteristics of viruses and understand why they are not regarded as living organisms.

Answer 41

Viruses all have nucleic acids (genetic info) and proteins. Some have membranes. They can store info, evolve, and reproduce. They are not regarded as living things however because they do not not respond to their environment, use/assimilate energy, maintain a constant internal environment, or composed of cells. Their reproduction is dependent of a living organism.

Question 42

Explain how viruses replicate and understand how they evolve.

Answer 42

Viruses replicate in 5 steps. 1 They attach to their host cell. 2 they make a hole and insert their genetic info into the host cell. 3 they use the cells proteins to replicate its own genetic material. 4 from the viruses replicated material, it is put together to make a new virus. 5 the new virus is released from the host cell. They can follow a lytic pathway which they are copied, assembled and bring about cell death rather quickly or they can follow lysogenic pathway where they are incorporated into the host's dna and copied into every new host cell. The way viruses reproduce in their host cells makes them particularly susceptible to the genetic changes that help to drive their evolution. The RNA viruses are especially prone to mutations.

Question 43

Describe the beneficial and harmful effects of viruses on humans.

Answer 43

Viral diseases are among the most deadly infections known. Viruses can provide immunity to bacterial infections and in the case of vaccines, can help produce more antibodies and memory cells for the future infection of that disease. Harmful effects are that the viruses take over and destroy body cells, cause the organism to become sick from the immune system fighting the virus; HIV causes an non functioning immune system.

Question 44

Describe the components of innate immunity, including physical barriers and internal defenses.

Answer 44

Innate immunity is nonspecific. It consists of the physical barrier - skin, fevers rising body temp to inactivate viruses, inflammation - rush of macrophages and blood to the area of infection so the macrophages and engulf the virus/dead cell particles. Proteins cause a chemical gradient that attracts phagocytes to an area of infection. Interferons prevent spread to other cells.

Question 45

Describe antibodies (as the humoral response of adaptive immunity), where they are produced and how they function.

Answer 45

Antibodies are specific cell surface proteins. On B cells they bind to specific antigens. Antibodies are produced by the B cells. Antibodies prevent pathogens from entering or damages cells by binding to them, they stimulate removal of pathogens by macrophages and other cells by coating the pathogen, and they trigger destruction of pathogens by stimulating other immune responses.

Question 46

Describe the cell-mediated response of adaptive immunity and how it functions.

Answer 46

Cell-mediated immunity is an immune response that does not involve antibodies, but involves the activation of phagocytes, antigen-specific cytotoxic T-lymphocytes, and the release of various cytokines in response to an antigen. Helper T cells provide protection against different pathogens. Killer T cells attack cells that are infected by viruses and that have viral antigen in their membranes. Helper T cells secrete cytokines that stim the proliferation of killer t cells. They stimulate division of B cells and more antibodies. They secrete messages that affect B cells, phagocytic cells, and other T cells.

Question 47

Describe immunological memory and understand how vaccines function.

Answer 47

Vaccines introduce dead or weak versions of infection to the body which activates naive B cells to produce antibodies and memory cells. If the person is exposed to an antigen that was introduced by a vaccine, because of the memory cells and antibodies produced by the B cells, the immune system can respond quickly. Memory cells are long-lived lymphocyte capable of responding to a particular antigen on its reintroduction, long after the exposure that prompted its production.

Question 48

Describe the different types of leukocytes and how they contribute to adaptive and innate immunity.

Answer 48

Neutrophils-Phagocytic specialists that work on bacterial infections; most abundant leukocyte/ Eosinophils-Mainly for allergic conditions such as asthma and hayfever and internal parasitic infections Basophils-Least numerous and least understood; store histamine and heparin (removing fatty substances from blood and important anticoagulant) Monocytes-Emerge from bone marrow while still immature and settle down in resident tissue to mature Lymphocytes-B-Lymphocytes-antibody-mediated immunity; produce antibodies to bind to an antigen for destruction by phagocytosis or other means:T-lymphocytes-cell-mediated immunity; release chemicals to punch holes in foreign cell; work mostly on viruses and cancer cells

Question 49

Describe the components of the lymphatic system and how they function in immunity and transport of materials.

Answer 49

The lymphatic system functions to absorb leaked intercellular fluid, absorb digest fat from SI and manufacture/store/transport many components of immunity. The lymph nodes contain T lymphocytes and macrophages, filter lymph, and are where B lymphocytes divide and differentiate. The spleen filters blood, stores extra rbc and platelets and b lymphocytes multiply and differentiate. The thymus gland secretes thymosin and matures stem cells into T lymphocytes. The red bone marrow manufactures blood cells. Yellow bone marrow - fat, bone, cartilage. Lymph vessels are how the lymph vessels transport the materials around the system

Question 50

Use a small crustacean (Daphnia) to explore a physiological response (heart rate) to external environmental factors.

Answer 50

Daphnia's heart rate is affected by many environmental factors. They are ectotherms which rely on the environment for body functions so when they are in a higher temp, their heart race increases and lower temp makes their heart rate decrease. When placed in ethanol, their heart rate decreases because it is a depressant, and when they are placed in nicotine or caffeine, their heart rate increases because they are stimulants. Higher heart rates can lead to overuse of the heart and low heart rates can mean that materials won't be circulated through the body at an efficient enough rate.

Question 51

Identify the major challenges for animals living in terrestrial environments (as opposed to living in aquatic environments) and how animals have evolved adaptations to overcome these challenges.

Answer 51

Challenges - gravity:structural adaptations such as the skeletal system and muscular system/desiccation:urinary system works to maintain osmotic balance of both water and critical ions/water for fertilization and development:internal fertilization or shells and internal developing embryos/UV radiation:produce more pigments like melanin

Question 52

Identify the three major types of skeletal systems found in animals and understand the advantages and disadvantages of each type of skeletal system.

Answer 52

Endoskeletons: adv - grows with organism and can support more weight. Disadv - not great leverage for muscle work, energetically costly because the bones are alive, and minimal protection (only rib cage and skull) exoskeleton : adv - protects all soft tissues and the structure of muscle attachments provide better leverage so animals are strong. Disadv - no growth/needs to shed, size limit (small organisms), energy cost is high. Hydrostatic : adv - not energetically costly and high flexibility. Disadv - requires moist environment and little protection.

Question 53

Identify the three major types of muscles (smooth, cardiac, and skeletal) and describe the function and location within the organism of each type.

Answer 53

Smooth muscle - GI tract/blood vessels/urogenital tract/involuntary/contracts when stretched (stomach)/ requires less ATP. Cardiac muscle - heart/involuntary/short cells/single nucleus/ controlled by nervous system/contracts to pump heart and blood through the body. Skeletal muscle - attached to skeleton/voluntary/long cells/multinucleated/striated/densely packed/contract to move the parts of the body and the whole organism.

Question 54

Describe the basic functional unit of muscle contraction (the sarcomere) and identify the structures found within this unit.

Answer 54

The sarcomere is a segment of myofibrils delimited by the z-line and made up of thick and thin filaments (myosin and actin respectively). The sarcolemma is the outer covering or membrane where action potentials occur, myofibrils are long protein fibers. Many myofibrils make up a muscle fiber.

Question 55

Understand the sliding filament theory of muscle contraction, including the roles of actin filaments, myosin filaments, ATP, and calcium ions.

Answer 55

Nerves release neurotransmitters that bind with receptors on the sarcolemma which starts the action potential. Ca2+ is released from sarcoplasmic reticulum and binds to troponin. The troponin changes shape and moves tropomyosin away from myosin binding sites. Myosin changes shape, binds to actin, and "pulls" thin filaments. ADP is released, ATP binds, and myosin releases actin. ATP is broken into ADP and Pi and myosin is ready to bind again.

Question 56

Understand how the nervous system, senses, muscular system and skeletal system work together to allow animals to function within their environment.

Answer 56

The senses gather information or stimuli from the environment (like heat from your hands touch receptors on a hot stove). The nerves receive those signals and transfer them through the nervous system where the CNS interprets those signals. The CNS sends out a response through the nervous system to the motor neurons which cause a response or movement in the muscles or glands that they act upon.

Question 57

Understand the need for regulation of water and solute content in organisms as an adaptation for living in different environments.

Answer 57

Osmotic regulation is the process of maintaining a characteristic of body fluids within a certain parameter. It is important for organisms in different environments because aquatic organisms are always surrounded by water and it is not as hard to retain water in their bodies. Terrestrial organisms had to adapt to retain water in their bodies so that they wouldn't dessicate. Organisms that transitioned from saltwater to freshwater and terrestrial land also had to adapt to regulate ions like sodium. Because sodium was not readily available like in seawater, they had to adapt to transport those ions into their bodies.

Question 58

Understand the organs and structures involved in osmotic regulation and water conservation.

Answer 58

Kidneys filter blood to produce urine. The nephron is the functional unit of the kidney and functions to filter the blood by absorbing water, ions, and secreting waste products. The ureter connects the kidney to the bladder and the urethra passes urine from the bladder to be secreted outside the body.

Question 59

Describe the functions of the mammalian kidneys in osmotic regulation, acid-base regulation, and excretion of nitrogenous wastes.

Answer 59

The kidney functions to filter blood, regulate pH, and excrete nitrogenous wastes. Under normal conditions, the kidney's main role in acid-base balance is through the excretion of acid in the form of hydrogen (H+) ions. The collecting duct can secrete hydrogen ions with a really high hydrogen ion concentration gradient if your body thinks its blood is too acidic. If the blood pH is too alkaline, then the collecting duct can secrete bicarbonate, which is a base, into the collecting duct and therefore cause the urine to become more alkaline. They filter blood and regulate osmotic regulation by absorbing/secreting ions such as sodium and chloride and absorbing or secreting water in the nephrons. The nitrogenous wastes produced by the body are filtered out of the blood and kept in the urine to be secreted from the body.

Question 60

Describe how analysis of urine components can be used to gather information about normal and abnormal physiology.

Answer 60

You can use urine analysis to detect the functioning of the kidney. If there is too much glucose in the blood, you can assume that the tubules are not reabsorbing the glucose or that there is too much glucose in the system. Same thing with proteins. If there are proteins in the urine, you may assume that the glomerulus is not functioning properly and allowing the proteins to exit the blood and enter the filtrate where they cannot be reabsorbed into the blood.

Question 61

Identify the structures of the basic functional unit of the mammalian kidney (the nephron).

Answer 61

Nephron is composed of the glomerulus, PCT, loop of Henle, DCT, and collecting duct.

Question 62

Understand the processes of glomerular filtration, tubular reabsorption, and tubular secretion; the regions of the nephron in which these occur; and the cellular mechanisms involved (e.g., active transport, passive transport).

Answer 62

Glomerular filtration: In Bowman's capsule, most solutes are filtered out of the filtrate. Only passive diffusion is needed here. Tubular reabsorption: In the proximal convoluted tubule, where ions are reabsorbed by active transport, water follows by osmosis, and nutrients are reabsorbed by active or passive transport. Tubular secretion: Occurs in the distal convoluted tubule. This is the active transport of substances from the blood into the tubule, in order to concentrate them for excretion.

Question 63

Understand the adaptations that allow organisms to reproduce on land.

Answer 63

Because terrestrial animals do not live in water for sperm to swim around in, land animals can move to water to reproduce - amphibians, they can produce spermatophore (packages of sperm for female to pick up), or they can fertilize internally (humans). They also have evolved to produce amniotic eggs (allows gas to be exchanged but not water and includes yolk to nourish the embryo) to protect the embryos and the placenta for embryos that develop within the mother.