Biology Past Paper PDF

Topic 2: Structure and Function Content Outline: Basic Anatomy and Physiology – Part 1 I. Anatomy – This is the study of structure; Physiology – This is the study of function. II. Hierarchy of multi-cellular organism’s structure: A. Cells – These are the basic unit of life. B. Ti...

Topic 2: Structure and Function Content Outline: Basic Anatomy and Physiology – Part 1 I. Anatomy – This is the study of structure; Physiology – This is the study of function. II. Hierarchy of multi-cellular organism’s structure: A. Cells – These are the basic unit of life. B. Tissues – These are composed from cells with common structure and function. (There are 4 tissue types in most animals.) 1. Epithelial Tissue (This tissue forms protective coverings of structures, such as organs, cavities, and skin.) a. They act as a barrier for various molecules. (This tissue relies heavily on the cell junctions to function.) 2. Connective Tissue (This tissue is for binding together and supporting the other tissues of the body.) a. Types of connective tissue cells: i. Loose connective tissue - This is the most abundant. (It basically acts as “filler material”.) ii. Adipose tissue (Fat cells) - These are for insulation, E storage, and padding. iii. Fibrous Connective tissue – These are composed of dense collagenous fibers. - Ligaments - For connecting bone to bone. - Tendons - For connecting bone with muscle. iv. Cartilage - This is a flexible support material. - Cartilage is also the initial framework for making bone. v. Bone (Osteo Tissues) This is made from cartilage that has undergone ossification. (Ossification means “The process of making bone”). – These cells build bone by depositing Calcium and Magnesium salts in cartilage. vi. Blood Tissue - This tissue connects the whole organism transporting gases, nutrients and wastes. - Plasma - This is the watery component containing dissolved substances. - Hematocrit - This is the cellular component- RBC’s, WBC’s, and platelets. - “Erytho” means “red”; “Leuko” means “white”; “cyte” means “cell” 3. Nervous Tissue - This tissue senses stimuli and relay messages. a. The basic structure is called a neuron. i. Dendrites – This part of the cell receives stimulus from the environment or another cell. ii. Body – This part collects and bundles the stimuli into one message. (Contains the organelles) iii. Axon – This part takes the information away from body toward the brain/muscle/gland. 4. Muscle Tissue -This tissue provides a pulling force within the body. a. Cells of this tissue are referred to as muscle fibers due to their long spindly shape. b. These cells are mostly composed of actin and myosin microfibrils. c. This tissue is the second largest consumer of energy in animals. (First is homeostasis.) d. Three types of muscle tissue in animals:  i. Skeletal - This is striated muscle. (means “striped”)(It is voluntary, meaning you control it.) ii. Cardiac - This is striated muscle. (It is involuntary, meaning the brain controls it; not you.) iii. Smooth - This is unstriated muscle. (It is involuntary.) (It functions in peristalsis - - rhythmic contraction of the digestive tract or in moving blood through blood vessels.) C. Organs – This functional structure is a collection of similar tissues working together. 1. They are positioned in two different cavities: a. Thoracic Cavity - This is above the diaphragm. It contains the heart and lungs and is protected by ribs. b. Abdominal Cavity - This is below the diaphragm. It contains the digestive, urinary, and reproductive organs. D. Organ Systems – These are composed of organs working together. (There are 11 systems in animals.) E. Organism – This when all the organ systems are working together to create a multi-cellular organism. (This is a great example of Emergent Properties.) Topic 2: Structure and Function Content Outline: Basic Anatomy and Physiology – Part 2 I. Homeostasis - Maintaining a steady internal state. A. Negative Feedback Loop – This stops a process already in motion and reverses the effect. B. Positive Feedback Loop - Enhances a process that is already in motion. C. To constantly monitor all the chemical processes occurring within an organism every second of everyday it is alive, requires a tremendous amount of energy. Therefore this is the number one energy expenditure by animals. The amount of energy needed to stay alive will be related to the amount of food they eat. II. Metabolism (The sum of all the chemical reactions occurring within an organism.) A. Heat Production vs. Food Intake vs. Activity 1. Endotherm – These organisms generate their body heat from within by breaking down their food; therefore they need to eat more to keep their bodies warm; therefore they are more active anytime of the year. 2. Ectotherm – These organisms obtain heat from the surrounding environment; therefore they need less food; therefore they are less active most of the time, especially when it is cold out. 3. Metabolic Rate vs. body size a. Small animalsneed more Eto counter their large loss of body heat. b. Large animalsneed less Eas they lose less body heat. c. Birdsrequire massive amounts of Eto counter the massive amount of body heat lost and needed to keep their giant breast muscles warm. III. Thermoregulation in Animals A. Regulator-Organisms that monitor temperature and adjust in a changing environment. This requires energy. B. Conformer-Organisms that match their body temperature to the environmental temperature. (Requires No energy. 1. These are incorrectly referred to as “cold” blooded animals. C. Adaptations in animals to aid in thermoregulation: 1. Insulation (hair, feathers, fat) Topic 2: Structure and Function Content Outline: Nervous Systems I. Evolution of a Nervous System A. Start with the evolution of an organism wide Nerve Net in Cnidarians. B. The evolution of a brain (a mass of neurons) leads to control of the system. It uses a nerve cord to control the body. C. The evolution of other sensory organs in the head region, called Cephalization, allows for reception and response to stimuli from the environment. II. Overview of the Nervous System: A. Sensory Input-Stimulus sent into the brain or spinal cord. 1. Sensory Receptors receive a stimulus from the environment. A stimulus is a form of energy such as electromagnetic (light), mechanical (pressure), and sound waves. B. Integration 1. This is the interpretation of the energy by the Central Nervous System (CNS). (Basically “thinking” about the stimulus) 2. This interpretation of the stimulus leads to a determination of the appropriate response. C. Motor Output (Out of the brain or spinal cord.) 1. The response is carried out by Effector Cells. a. Effectors are Muscles or Glands. (These can have an effect on your body.) D. Peripheral Nervous System (PNS) 1. This includes the Sensory Receptors and Motor Nerves. 2. Divided into the autonomic and somatic nervous sytems. III. Neuron Structure (Nerve Cell) A. Cell Body-This takes stimuli from different dendrites and compiles the energy into one signal. (Like a funnel) B. Dendrites -These collect and carry stimuli Energy in to the cell body. (They cover a large area.) C. Axon-This one arm carries the one compiled signal away toward the next neuron or effector cell. D. Myelin Sheath-This is a lipid layer of insulation around the axon created by Schwann Cells. It prevents the electrical energy of the neuron from burning the overlying muscle tissue. (It is analogous to the rubber covering on electrical wires.) F. Synapse-This is the gap between neurons or between a neuron and an effector cell. 1. Neurotransmitter - This is the chemical, produced by the neuron, used to transmit the signal across the gap. a. The most common neurotransmitter is Acetylcholine. IV. Reflex Arc (The simplest neural pathway.) A. A stimulus energy is detected by a Sensory Neuron. (Carries the energy signal to the spinal cord) B. An Interneuron (of the CNS – spinal cord) relays the energy back out to the motor nerve instead of to the brain. (“inter” means “go between”… between the sensory and motor neurons.) C. The energy is carried out of the CNS by the Motor Neuron. It carries the energy to an effector cell, usually a muscle. D. This is why you do not think about a reflex, it just happens. The stimulus never made it to the brain for integration. Topic 2: Structure and Function Content Outline: Sensory Mechanisms – Part 1 I. Sensation of Hearing A. This sensation is accomplished by mechanoreceptors located in the inner ear. (Sound is basically hairs bending.) B. Structure of the human ear 1. Outer Ear- This part is for the collection of sound waves from the external surrounding environment. a. Pinna -This cartilaginous structure acts like an antenna for collecting sound waves. b. Auditory canal-This concentrates the energy as it moves toward the middle ear. c. Tympanic Membrane (A.K.A. ear drum)- This structure converts the sound wave energy into vibrations. 2. Middle Ear - This part is for the amplification of energy traveling toward the inner ear. a. Malleus (A.K.A. the hammer)* b. Incus (A.K.A. the anvil)* *smallest bones in the human body c. Stapes (A.K.A. the stirrup)* This bone bangs on the oval window to create ripples inside the cochlea. i. These bones are responsible for amplifying the vibration energy. d. Eustachian tube – These tubes, that connects with the throat, acts as a pressure valve for the ears. e. Oval window-This structure converts the amplified vibration energy into fluid wave energy. 3. Inner Ear -This part is where the transduction of fluid waves into electrical energy occurs – the type of energy that the brain can understand. a. Cochlea “snail shell shaped” - This organ is located in the temporal bone of the skull. i. It is filled with a fluid called perilymph. (This fluid is used to make ripples.) ii. The Vestibular Canal runs on top of the Cochlear duct. (A “vestibule” is a covering.) iii. The Tympanic Canal runs on the bottom of the Cochlear duct. It ends at the round window. iv. The Cochlear Duct contains the Organ of Corti (Where the hairs are located.) - Basilar membrane -contains the mechanoreceptor hairs - Tectorial Membrane-bends the hairs as the ripple energy passes over top. - Hairs bend causing neurons of the auditory nerve to create an action potential. (Electrical energy). b. Round Window - This structure absorbs the ripple so as not to create waves in opposite direction. C. Volume (A.K.A. loudness) 1. This term refers to the sound wave height – (Tall = loud); (Small = soft) D. Pitch (A.K.A. Frequency) This term refers to the “number” of sound waves to hit the tympanic membrane per second. 1. It is measured in hertz (Hz) – (20 -20,000 – human hearing. Most animals can go much higher than humans. II. Sensation of Balance and Motion A. These are accomplished by mechanoreceptors (hairs bending again) in the Inner Ear. B. Vestibule -This is the covering of the Utricle and Saccule – These structures are perilymph reservoirs. C. Semi-circular canals - There are 3 on each side of head. These are the actual organs that detect these sensations. 1. The canals are filled with perilymph fluid. 2.3 canals: (90⁰ -detects up/down; 45⁰ - detects horizontal/vertical; 0⁰ -detects left lean/right lean) 3. Ampulla -This is the swelling located at the end of a canal. This swelling contains the cupula. 4. Cupula –This structure contains the embedded mechanoreceptors (Hairs that bend.) a. Movement of the body causes the perilymph to “flow” through the canals and bend the cupula hairs. b. Cupula bends hairs causing depolarization in neurons and the energy of motion is converted to electrical energy. III. Sensation of Taste A. This is accomplished using receptors in the nose (olfactory – means “smell”) and mouth. (gustatory – means “taste”) B. Chemicals are detected by different neurons upon contact. 1. The five taste senses are: sweet, sour, bitter, salty, and umami (means “savory”… applies to meat taste.) Taste is 80 % SMELL and 20 % TASTE – What if you have a cold? Food seems tasteless. Topic 2: Structure and Function Content Outline: Sensory Mechanisms – Part 2 I. Sensation of Sight (The eyes are a collection of photoreceptors.) A. Types of light detecting structures: 1. Oscilli – As seen in Cnidarians and Bi-valves. 2. Eye cup – As seen in Platyhelminthes. 3. Eyes with a lens as seen in most other animals. a. Compound Eye– Found in invertebrates, such as insects. i. Many ommatidia working together. (Produces multiple pictures of the same object) ii. This type of eye is great for detecting movement. b. Single Eye– Found in mollusks and vertebrates. (These are good for detecting definition.) B. Anatomy (structure) of the Human Eye: 1. Sclera – This is referred to as the eye white. 2. Choroid – This layer contains the blood vessels and black pigment for reducing sun light glare. 3. Conjunctiva – This layer is involved with mucous production to keep the eye cells moist. (Conjunctivitis…is the inflammation of this tissue layer.) 4. Cornea – This layer is the clear part of the sclera. (It also acts as a fixed lens and prevents debris from entering.) 5. Iris – This is the “colored” choroid (It controls the amount of light entering the eye through the pupil.) a. It is operated by smooth muscle automatically for you. (Autonomic nervous system) 6. Retina – This layer of the eye is the site of the photoreceptors.(It appears yellow upon dissection.) a. Rods - This receptor cells are for seeing black, white, and shades of grey. i. They are the most abundant in all animals having these structures. ii. They possess Rhodopsin Pigment. b. Cones - These receptor cells are used for seeing color. i. They are outnumbered 20 :1 by the rods. ii. They are found in vertebrates: but not all. iii. They possess Photopsin Pigments (red, blue, green) (Color-blindness –sex linked recessive.) (The genes for making these pigments were never in the parent’s gametes.) 7. Lens – This structure focuses light. (It is made of a transparent, stretchable protein called crystalline.) a. Accomodation (This is the “focusing” of the eye for near vs. distant vision… This requires it to stretch.) i. Stigmatism – This term refers to a misshaped lens. ii. Myopia – (A.K.A. nearsighted) You can’t see far away objects clearly. iii. Hyperopia – (A.K.A. farsighted) You can’t see close up objects clearly. iv. Presbyopia – Term refers to lens degeneration associated with old age. v. Cataract – This term refers to a “cloudy lens”. vi. Glaucoma – Condition of having too much vitreous humor; results in too much pressure in the eye. 8. Ciliary Body – These are the muscles that stretch the lens. 9. Aqueous Humor – This is the fluid in the front of the eye. (It is mostly water… “aqueous”; humor means “fluid”.) 10. Vitreous Humor – This is the fluid in the back of the eye (It is jelly-like… “vitreous”) It gives the eye its shape.  12. Optic Nerve – There is one for each eye. (It takes the action potential to the brain.) 13. Optic Chiasm – Collects rights and lefts into one side of brain. (Located in the base of the brain) 14. Lateral Geniculate Nuclei – These groups of neurons make the right or left “side” picture. 15. Primary Visual Cortex of the Occipital lobe of cerebrum - The site of integration of “halves” into 1 picture.. Topic 2: Structure and Function Content Outline: Sensory Mechanisms – Part 3 I. Locomotion – (A.K.A movement) This term refers to active movement of an organism or object using muscles and skeleton. A. This process is the second largest consumer of ATP energy within an organism because: 1. Organism has to overcome the force of gravity AND 2. Overcome the force of friction (resistance). B. Locomotion is accomplished by the use of the skeleton. 1. There are skeletons made of bones, such as in Starfish, fish, amphibians, reptiles, birds and mammals. 2. There are skeletons made of water pressure (hydroskeleton), such as in earthworms. 3. There are skeletons on the outside of the body, called exoskeletons, such as on insects and other arthropods. C. Locomotion is also accomplished by the use of muscles. 1. The muscles associated with movement are called skeletal muscle. They are Striated (striped). a. The striations (strips) are created by the proteins microfilaments Actin and Myosin. b. These muscle cells all run in the same direction. This gives them greater pulling strength. i. Muscles can only pull on skeletons. They cannot push on skeletons. c. These are the only muscle you can control. This is called voluntary movement. (You must think it.) 2. The muscles of your heart are called cardiac muscle. They are also striated. a. They have a crisscrossing “net-like” structure. This gives it greater compression (squeezing) strength. b. You cannot control this movement. It is called involuntary movement. (You do not think about it.) 3. The muscles of your digestive tract or iris are operated by smooth muscle. They have no striations (stripes.) b. You cannot control this movement. It is called involuntary movement. (You do not think about it.) C. Types of environments dealing with locomotion: 1. Water (Organisms are swimming or floating.) a. Little gravity to overcome because of buoyancy; but much friction (water resistance). i. Having a fusiform (means “torpedo shaped”) body lessens friction. 2. Land (Organisms are standing/walking/running.) a. Much gravity to overcome; but little friction (air resistance). i. Organisms have strong muscular limbs to overcome gravity. 3. Air (Organisms are flying or gliding.) a. Much gravity to overcome and much friction to overcome (air resistance). i. These require that massive amounts of energy be consumed to overcome. Topic 2: Structure and Function Content Outline: Circulatory and Immune Systems I. Circulatory System - Responsible for connecting all the cells of the whole organism. A. The Circulatory System distributes nutrients, oxygen, hormones, and functions in waste retrieval. II. Evolution of the Circulatory system: A. It started with a Gastrovascular Cavity. (As seen in Cnidarians and Platyhelminthes.) B. Open Circulatory system is one type that evolved. (Arthropods and some Mollusks) 1. Blood bathes the organs by moving through sinuses (spaces). 2. The system has a tubular heart with directional arteries to distribute blood. C. Closed Circulatory system (Annelids, some mollusks, vertebrates) 1. Blood is confined to traveling through blood vessels under pressure. 2. A muscular chambered heart mostly (Not in annelids.)(2,3,4 chambers) a. Atriums – These chambers receive blood coming into the heart. i. They are composed of a thin layer muscle tissue. b. Ventricles – These chambers pump blood away from the heart. i. They are composed of a thick layer of muscle tissue. 3. Mammals, birds, reptiles, and amphibians have a Double loop system. i. One loop for getting oxygen; one loop for delivering oxygen. 4. Echinodermata have a water vascular system with three parts ( madreporite, Tube feet, and canals.) III. Blood Vessel types of the body: A. Arteries – These are large blood vessels carrying blood away from the heart. B. Arterioles – These are medium sized vessels carrying blood away from the heart. C. Capillaries – These are the smallest blood vessels where nutrients and oxygen diffuse out. D. Venules – These are small blood vessels that collect waste materials from the tissues. E. Veins – These are large blood vessels that carry blood toward the heart. IV. Blood distribution A. During digestion of food – The blood mainly is in the digestive organs. 1. Swimming? The blood is not in the muscles, which are needed to swim, so you cramp if you go swimming right after eating. So wait 30 minutes. B. During Exercise – The blood is mostly in the muscles and skin; not the digestive organs. V. Types of Blood cells: A. Erythrocytes - These are red blood cells RBC’s (“erythro” means “red”; “cyte” means “cell”) 1. Hemoglobin uses iron (Fe) to hold oxygen. (“heme” means “iron”) a. Each RBC can hold 1 billion oxygen molecules. B. Leukocytes - These are white blood cells- WBC’s (“leuko” means “white”) 1. They protect our bodies against invading organisms or materials. 2. Some of these cells (B-Lymphocytes) make antibodies to help clean up your blood of pathogens (disease causing agents, such as bacteria and viruses.) 3. Some of these cells (T-Killer Lymphocytes) kill infected cells. C. Platelets – These are pieces of RBC’s used for making clots. VI. Immunity A. This term refers to an organisms ability to fight/protect itself from pathogens, toxins, and parasites. B. There are two types of immunity: 1. Innate Immunity (A.K.A. General Immunity) a. These are defenses you are born with, such as skin, tears, mucus in your nose and ears. b. For plants, it is bark, thorns, spines on a cactus, bad tasting chemicals/secondary compounds. 2. Specific Immunity(Immune Response) a. This uses the Lymphocytes to attack specific pathogens, such as Chicken Pox. b. This type of immunity is acquired (received by you) in two ways: i. Active immunity  You have to get and then fight the pathogen. (Chicken Pox is an example.)  You make memory cells to fight future infections. It takes less time to get better.  Primary Immune Response refers to the first time your lymphoctyes are activated due to a specific antigen. It is slow and may take many days to produce antibodies and memory cells to prepare for the Secondary Immune Response. The secondary immune response is a second exposure to the same antigen, which occurs faster and stronger because memory cells are already available to respond to the antigen.  You have to get a shot (immunization) to make the memory cells. The shot contains weakened viruses, so you hopefully do not get sick. Some immunizations only last a couple of months or years. ii. Passive Immunity  Passive immunity is across the placenta, through breastfeeding, or when you receive a shot or transfusion of already make antibodies/immunoglobulins.