HESI A2 BIOLOGY VERSION 2 STUDY GUIDE Complete

  Biology – Scientific study of life. Hierarchic organizational system for nomenclature: Kingdom, Phylum, Class, Order, Family, Genus, and Species. Kingdom is the largest and most inclusive while species is the most restrictive. The scientific method: 1. Observation: New observations made/ previous data collected and studied. 2. Hypothesis: Statement or explanation of certain events or happenings. 3. Experiment: Repeatable procedure of gathering data to support or refute the hypothesis 4. Conclusion: Where the date and its significance are fully explained. The most significant aspect of water is the polarity of its bonds that allow for hydrogen bonding between molecules. Several resulting benefits of hydrogen bonding (intermolecular bonding): 1. Waters high specific heat capacity. (specific heat – amount of temp needed to raise temp of 1 gram to 1 degree Celsius). Due to waters (H2O) high specific heat it’s able to resist changes in temperature and can stabilize environments. 2. Hydrogen bonding also results in strong cohesive (two molecules of likeness stick together) and adhesive (two molecules attract that are different) properties. Cohesion example – water tends to run together on newly waxed car. Adhesion example – When water is spread on the wall some sticks. - When water freezes it’s known as lattice crystal (only solid that floats on water). 3. The polarity of water also allows it to act as a versatile solvent. Biologic Molecules include: Carbohydrates, lipids, proteins, and nucleic acids. 1. Carbohydrates – generally long chains or polymers of sugar. The most important functions: storage, structure, and energy. Carbohydrates form the backbone of DNA and RNA. 2. Lipids (AKA Fats) – Saturated fats contain no double bonds hydrocarbon tail, as a result saturated fat are solid a room temp and related to cardiovascular problems. Unsaturated fats: have one or more double bond. o Phospholipids – two fatty acids varying in length bonded to a phosphate group. Phosphate group is charged and therefore polar and soluble in water which is important for cellular membranes which creates a barrier to protect the cell. o Steroids – lipids that are important because they are a precursor to most hormones and drugs. 3. Proteins – Most significant to cellular function and are polymers of 20 molecules called amino acids. Proteins are largest biologic molecule and are used to catalyze reactions with enzymes. Nearly all cellular function is catalyzed by some type of enzyme. 4. Nucleic acids – Important for a cells inheritance. DNA: Contains code necessary for replication. RNA is used to transfer info from DNA to protein level and as a messenger in most species of genetic code. Metabolism – is the sum of all chemical reactions that occur in an organism. In a cell, reactions take place in a series of steps known as metabolic pathways from high energy to low energy. The Cell – Is the fundamental unit of biology. There are two types of cells: Prokaryotic and Eukaryotic. o Prokaryotic cells: lack a defined nucleus and do not contain membrane bound organelles. o Eukaryotic Cells: Have a membrane bound enclosed nucleus and a series of membrane bound organelles that carry out the functions of the cell. The eukaryotic cell is more complex than prokaryotic. Several organelles functioning in a cell: 1. Nucleus – contains DNA of the cell organized in masses known as chromosomes. Chromosomes contain all genetic info for regeneration (replication and repair) of the cell and instructions for the function of cells. 2. Ribosomes – organelles that read RNA produced in the nucleus and translate genetic instructions to produce proteins. Cells with a high rate of protein synthesis tend to have large numbers of ribosomes. o Ribosomes found in two places: Bound ribosomes found attached to endoplasmic reticulum (ER) and free ribosomes are found in cytoplasm. o Rough ER: responsible for protein synthesis and membrane protection. o Smooth ER: lacks ribosomes and functions as detoxification and metabolism of multiple molecules. 3. Golgi Apparatus – Packaging, processing, and shipping organelle. Transports proteins from the ER throughout the cell. 4. Lysosomes – intracellular digestion takes place here. Lysosomes can hydrolyze (with hydrolytic enzymes) proteins, fats, sugars, and nucleic acids. Lysosomes normally have an acidic environment (around 4.5 PH) 5. Vacuoles – membrane enclosed structures, process of phagocytosis (eating of other cells) takes place here. Uptake of food through the cell membrane creating food vacuole. Plant cells have central vacuole that function as storage, waste, disposal, protection, and hydrolysis. 6. Mitochondria and chloroplast – Produce cell energy: o Mitochondria - are found in most eukaryotic cells and are the site of cellular respiration. o Chloroplast – are found in plants and are the site of photosynthesis. 7. Cellular membrane – most important component of a cell contribution protection, communication, and the passage of substances into and out off a cell. o Cell membrane is composed of a bilayer of phospholipid with protein, cholesterol, and glycoproteins peppered throughout. o Phospholipids are amphipathic molecules creating bilayers making it selectively permeable. 8. Cellular respiration: Two catabolic pathways that lead cellular energy production: cellular respiration and fermentation. Cellular respiration produces far more energy that it’s anaerobic counterpart, fermentation. o Respiration formula: C6H12O6 + 6O2  6CO2 + 6H2O o There complex steps to cellular respiration: ATP – energy currency of a cell, NADH – reducing agent and is a vehicle of stored energy (this molecule is a precursor to greater amounts of ATP being produced in final steps of respiration). 1. Glycolysis – conversion of glucose to pyruvate taking place in the cytosol of the cell and produces 2 ATP, 2 pyruvate, and 2 NADH molecules. 2. Citric Acid Cycle (Krebs Cycle) – takes place in the matrix of the mitochondria and for 1 single glucose molecule – 2 ATP, 6 CO2, and 6 NADH molecules are produced. 3. Electron transport Chain – Remarkable energy harvest here – 28 to 32 ATP molecules for every single glucose molecule. This conversion results in overall ATP production numbers of 32 to 36 ATP molecules for every glucose molecule consumed. o Photosynthesis – The reverse of cellular respiration: 6CO2 + 6H2O + Light Energy  C6H12O6 + 6O2 o The only noticeable difference is light energy. o Photosynthesis consists of two different stages: light reactions and Calvin Cycle. 1. Light reactions – cell accomplishes production of ATP by absorbing light and converting energy to split a water molecule and transfer the electron (which creates NADPH). 2. These molecules are then used in the Calvin Cycle to produce sugar. These sugars are consumed by the organisms or by the plant itself to produce energy by cellular respiration. Hesi Hint: The raw materials for cellular respiration are Glucose and Oxygen and the products are water, carbon dioxide, and ATP. The products of cell respiration is oxygen and glucose become the raw materials of cellular respiration. Three types of cellular reproduction: Asexual and sexual reproductions – 1. Binary fission 2. Mitosis 3. Meiosis Two types of asexual reproduction are binary fission and mitosis. 1. Binary fission – Chromosomes bind to the plasma membrane where it replicates. Then cell pinches in two producing two identical cells. 2. Mitosis – Occurs in 5 stages Prophase, Prometaphase, Metaphase, Anaphase, and Telophase before pinching in two identical cells in a process called cytokinesis. o Prophase – the chromosomes are visibly separate, and each duplicated chromosome has two noticeable sister chromatids. o Prometaphase – The nuclear envelope begins to disappear, and the chromosomes begin to attach to the spindle forming along the axis of the cell. o Metaphase – All chromosomes align along the metaphase plate or the center of the cell. o Anaphase – Chromosomes start to separate. In this phase the chromatids are considered separate chromosomes. o Telophase – The final phase with chromosomes gathering either side of the now separation cell. This is the end of mitosis. The second part of mitosis is known as cytokinesis: During this phase the cell pinches in two creating two separate identical cells. o Sexual reproduction: two cells contribute genetic material, resulting in significantly greater variation. This process is called meiosis! Two distinct stages known as meiosis 1 and 2 resulting in 4 daughter cells. Each of these daughter cells contain half as many chromosomes as the parent. Preceding these events is period called interphase. o Interphase – Chromosomes are duplicated during meiosis and the cell prepares for division. - The significant difference between meiosis and mitosis occurs in prophase 1. o During this phase chromatids of homologous chromosomes cross at numerous sections. Small sections of DNA are transferred between chromosomes resulting in increased genetic variation. Genetics: o Gregor Mendel discovered the basic principles of genetics using garden peas with a tool known as the Punnett square. 1. Alleles – Alternative versions of a gene and can be one of two types: dominant and recessive. If both alleles are the same type they are known as homozygous and if they are different they are known as heterozygous. Dominant alleles are capitalized, and recessive alleles are lower case. 2. Genotype – the combination of alleles 3. Phenotype – what traits will be expressed DNA: o Is the genetic material of a cell and is the vehicle of inheritance. o Watson and Crick described the structure of DNA to be double helical structure that contains the four nitrogenous bases: adenine, thymine, guanine, and cytosine. Each base form hydrogen bonds with another base of complimentary strand. 1. Adenine bonds with thymine. 2. Guanine bonds with cytosine. o Transcription: an RNA strand, complimentary to the original strand of DNA, is produced. The piece of genetic material produced is called messenger RNA (mRNA). The RNA strand has identical bases of DNA except for uracil, which is substituted for thymine. o Every group of three bases along the stretch of RNA is called a codon and each of these codes for a specific amino acid. The anticodon is located on the unit called transfer RNA (tRNA), which carriers’ specific amino acid. Anatomy and physiology Medial plane – toward the center Coronal plane – separates back and front (Think coronal suture on the top of the skull, it separates the frontal bone and parietal bones) Sagittal plane – Separates the left and right sides (think of the sagittal suture of the skull, it separates the parietal bones) Transverse plane – is a cross section of the body dividing it into 4 equal parts. Anatomic position – The body is erect, feet are slightly apart, the head is held high, and the palms of the hands are facing anteriorly. o Superior (above), o Inferior (below), o Anterior (facing forward), o Posterior (toward the back), o Medial (toward the midline), o Lateral (toward the sides), distal (further from point of attachment usually references limbs), and o Proximal (closer to point of attachment). Major body cavities o Dorsal cavity: includes cranial and spinal cavities o Ventral cavity: includes the orbits and the nasal, oral, thoracic, and abdominopelvic cavities Histology – study of tissues Four fundamental tissues are: o Epithelial Tissue: cells that cover, line, and protect the body and its internal organs. o Connective Tissue: is the framework of the body, providing support and structure for the organs. o Nerve Tissue: is composed of neurons and connective tissue cells that referred to as NEUROGLIA. o Muscle Tissue: have the ability to contract and shorten. Muscle tissue is classified as voluntary muscle (smooth or cardiac muscle tissue). Cell: is the basic unit of life and the building block of tissues and organs. o The Nucleus : contains DNA (deoxyribonucleic acid) and ribosomes are especially important in the synthesis of proteins. o Proteins include enzymes that regulate all chemical reactions. Mitosis and Meiosis o Mitosis – is necessary for growth and repair. The DNA is duplicated and distributed evenly to two daughter cells. o Meiosis – is the cell division that takes place in the gonads, that is, the ovaries and testes. ▪ In the process of meiosis, the chromosome number is reduced from 46 to 23 so when the egg and the sperm unite in fertilization, the zygote will have the correct number of chromosomes. The Skin – Largest organ of the body. Consist of two layers. o Epidermis: The outermost protective layer made of dead, keratinized epithelial cells o The layers of the EPIDERMIS from the outer layer to the inner layer are: • Stratum Corneum, • Stratum Lucidum, • Stratum Granulosum • Stratum Germinativum (includes the stratum basale and stratum spinosum), where mitosis occurs. Acronym: Cute little Grass Hopers Smell Bad (Inner to outer) ▪ Epidermal cells contain protein pigment called melanin, which protects against radiation. o Dermis: The underlying layer of connective tissue with blood vessels, nerve endings, and the associated skin structures. The Dermis rest on the subcutaneous tissue that connects the skin to the superficial muscles. o The inner layer of skin is the dermis: composed of fibrous connective tissue with • Blood Vessels, • Sensory Nerve Endings, • Hair Follicles • Glands There are two types of sweat glands: 1. Eccrine 2. Apocrine Two types of sweat glands: o Eccrine: Regulate body temperature by releasing a watery secretion that evaporates from the surface of the skin. o Apocrine: Armpits and groin, display apocrine secretion. This secretion contains bits of cytoplasm from the secreting cells which attracts bacteria resulting in body odor. o The Sebaceous gland: releases oily secretion (sebum) through the hair follicles that lubricates the skin and prevents drying. Sebum is produced by the holocrine system. Appendages of the skin include hair and nails: o Both are composed of a strong protein called Keratin Skeletal system: Body framework consists: of ▪ Bone ▪ Cartilage ▪ Ligament ▪ Joints Functions of the skeletal system: o Include support, movement, blood cell formation (Hemopoiesis), protection of internal organs, detoxification, provision for muscle attachment, and mineral storage. (Calcium and phosphorus are stored in skeletal system). Bones are classified by shape: o Long bones o Short bones o Flat bones o Irregular bones o Sesamoid bones Long bone: o Irregular epiphysis (end) at each end composed of mainly ▪ Spongy (cancellous) ▪ Shaft (diaphysis which composed mainly of compact bone) at each end. Compact bone: o Cells that form compact bone ▪ Osteoblasts: when they become fixed in the bone matrix, they stop dividing but continue to maintain bone tissue as osteocytes. The Axial Skeleton: Skull, vertebral column, 12 pairs of ribs, and sternum o The Skull has 28 bones total when including the six bones (ossicles which include malus, incus, and stapes which are located in the ear) 14 cranial vault bones and 14 facial bones. o The Mandible is the only moveable bone of the skull (remember bones of the skull) Vertebral column: Part of the Axial Skeleton o Divided into 5 sub sections: • 7 cervical vertebra, • 12 thoracic vertebrae • 5 lumbar vertebrae • 5 sacral vertebrae (which fuse to form the sacrum), and coccygeal vertebrae (tailbone) Acronym: Coffee (cervical) at 7, Tea (thoracic) at 12, and liquor (lumbar) at 5:00PM. The Appendicular Skeleton: Includes Girdles and Limbs ▪ The upper portion consists of: • The Pectoral Girdle/Shoulder Girdle • The Clavicle • The Scapula • Upper Extremity ▪ The lower portion consists of: • Pelvic Girdle/ OS Coxae (known the bones of appendicular skeleton) Muscular system: produce movement by contraction response to nervous system. ▪ Muscle contractions result from sliding together of myofibrils, which in turn are made up of still smaller unites called Sarcomeres (smallest muscle fiber). ▪ Calcium and adenosine triphosphate (ATP) must be present for a muscle to contract. ▪ Nervous stimulation from the motor neurons causes the release of calcium ions from the sarcoplasmic reticulum. Using energy supplied by the ATP, the filaments slide together to produce contraction. The Skeletal system: o Which makes up the muscular system, are also called voluntary muscles – because they are under conscious control. ▪ Prime mover – executes a given movement ▪ Antagonist – is the opposite of prime mover. ▪ Synergist – work together in cooperation with the prime mover. ▪ Flexors – reduce the angle at the joint. ▪ Extensors – increase the angle at the joint. ▪ ABducters – draw a limb away from the midline. ▪ ADDucters – return the limb closer to the midline adding to the body. The Nervous System o Brain and Spinal Cord: ▪ Seeing ▪ Hearing ▪ Tasting ▪ Smelling ▪ Touching examples of perception). o It enables us to think, reason, remember, and carry out abstract ideas. o Nervous system works with skeletal muscle to make body movements. o Nervous system works closely with endocrine system for digestion and reproduction. o All actions of the nervous system depend on transmission of nerve impulses over neurons, or nerve cells, the functional units of the nerve system. The Neuron – Main parts: cell, body axon, and dendrites. o Dendrites transmit the impulse towards the cell body. o Axons transmit the impulse away from the cell body. (Think axons away) Division of nervous system – Central nervous system and peripheral nervous system. ▪ CNS: Spinal cord and brain. • Sensory (Afferent) transmits nerve impulses towards the CNS. • Motor (Efferent) transmits nerve impulses away from the CNS toward organs: muscles, glands, and digestive tract. ▪ PNS: all other neurons in the body. - Major parts of the brain – cerebrum, cerebellum, and medulla oblongata. ▪ Cerebrum – associated with movement and sensory input. ▪ Cerebellum – responsible for muscular coordination. ▪ Medulla oblongata – controls vital functions such as respiration and heartbeat. ** ▪ Spinal cord – 18 inches long, extends from foramen magnum (base of skull) to the first or second lumbar vertebrae. ▪ 33 pairs of spinal nerves exit the spinal cord. ▪ Simple (spinal) reflexes only move through the spinal cord and do not reach the brain. HESI HINT: Most reflex pathways travel to and from brain in ascending and descending tracts of the spinal cord. Sensory impulses enter the dorsal horns of the spinal cord, and motor impulses leave through the ventral (leave) horns. The Endocrine System: o Assists the nervous system in homeostasis and plays important roles in growth and sexual maturation. The endocrine and nervous system meet at the hypothalamus and pituitary gland. o The hypothalamus governs the pituitary gland – the hypothalamus is controlled by the feedback of hormones in the blood. o Hormones – chemical messengers that control growth, differentiation, and metabolism of specific target cells. Two major hormone groups – steroids and non-steroids o Steroid hormones have direct effect on DNA o Non-steroid hormones are protein hormones. ▪ Endocrine glands main function: • production of hormones. Other organs like stomach, small intestine, and kidneys also produce hormones. HESI HINT: hormones are released during stress from adrenal cortex, the hypothalamus, and posterior/anterior pituitary gland. Cortisol – released from adrenal cortex reduces inflammation, raises blood sugar level, and inhibits the release of histamine. Pituitary gland nick named “the master gland” o Pituitary gland is attached to the hypothalamus by the stalk called the infundibulum. o The pituitary gland has two major portions: ▪ The anterior lobe ▪ The posterior lobe. Tropic hormones – hormones of the anterior pituitary gland. o Tropic hormones include: ▪ Anterior lobe pituitary gland) : STH ▪ Growth Hormone (GH) ▪ Adrenocorticotropic hormone (ACTH) ▪ Thyroid-stimulating hormone (TSH) ▪ Follicle Stimulating hormone (FSH), and Luteinizing hormone (LH). Pituitary posterior lobe includes: ▪ oxytocin (the labor hormone) ▪ antidiuretic hormone (ADH). Endocrine glands include: ▪ Thyroid ▪ Parathyroid ▪ Adrenals ▪ Pancreas ▪ Gonads (testes and ovaries). Circulatory system o Whole blood consists of 55% plasma o 45% formed elements: Erythrocytes, leukocytes, and platelets. o All the formed elements are produced from stem cells in the red bone marrow. ▪ Erythrocytes – Red blood cells: modified for transport of oxygen (bound to the protein pigment Hemoglobin) ▪ Leukocytes – white blood cells: 5 types of white blood cells. 1. Neutrophils and monocytes: active in phagocytosis. 2. Lymphocytes: antibody formation. o Platelets – active in the process of blood clotting. o Blood transports oxygen and carries away carbon dioxide and metabolic waste. The Heart: o Double pump that sends blood to the lungs for oxygenation through the pulmonary circuit. o Blood is received by the atria and is pumped into circulation by the ventricles. o Valves between the atria and ventricles include the tricuspid and bicuspid o ***Tricuspid on the right side of the heart. o ***Bicuspid on the left side of the heart. o ***Semilunar valves are found at the entrances of the pulmonary trunk and aorta. o ***Coronary arteries supply blood to the heart muscle (myocardium). o ***Blood drains from the myocardium directly into the right atrium through the coronary sinus. o Intrinsic beat – initiated by the sinoatrial node and transmitted along a conduction system through the myocardium. (***this wave is what is measured during EKG). o Cardiac cycle – from end of one ventricular contraction to end of the next ventricular contraction. o Contraction – Systolic o Relaxation – Diastolic Vascular system: o Arteries – carries blood away from the heart. o Veins – carries blood towards the heart. o Capillaries – smallest vessels: where exchange of water, nutrients, and waste products take place between the blood and surrounding tissues. Systematic arteries: o Aorta – sends branches to all parts of the body. o Arteries – become thinner as they travel away from the heart. o Arterioles – smallest arteries. o Superior and Inferior Vena Cava: large veins that empty into the RIGHT atrium of the heart. o Vasoconstriction and Vasodilation: Results from contraction and relaxation of smooth muscle in the arterial walls. Respiratory system: Include nose, pharynx, larynx, trachea, bronchi, lungs, with their alveoli, diaphragm, and muscles surrounding the ribs. - Medulla of the brain controls respiration. o External respiration- refers to the exchange of gases between the atmosphere and the blood through the alveoli. o Internal respiration: refers to exchange of gases between the blood and the body cells. o Cilia: line the upper passageways of the nose to trap debris and keep foreign substances from entering lungs. o Inhalation: requires the contraction of the diaphragm to enlarge the thoracic cavity and draw air into the lungs. o Exhalation: is a passive process during which the lungs recoil as the respiratory muscles relax and the thorax decreases in size. o Oxygen carried in blood is bound to hemoglobin in the red blood cells. o Carbon dioxide: Regulator of blood PH. Alimentary Canal: digestive tube consists of mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum, and anus. Accessory organs of digestion: liver, pancreas, and gallbladder. o Saliva contains an enzyme known as amylase that starts the digestion of complex carbohydrates. o Bolus – Ball of food Digestive tract has 4 main layers: – From inner to outer: o the Mucous membrane o the Submucous layer o the Muscular layer o the Serous layer Gastric glands: secrete hydrochloric acid that breaks the food down. Chyme – soupy substance created after the bolus is churned by the stomach muscles. Stomach – stores food and regulates the movement of food into the small intestine. Small intestine – works with the pancreas to create enzymes for the food. Pancreas – contributes water to dilute chyme and bicarbonate ions to neutralize the acid from the stomach. Nutrients: are absorbed through the walls of the small intestine. o All nutrients then enter the hepatic portal for decontamination. Villi: Small finger like projections greatly increase surface area of the intestine wall. o Large intestine reabsorbs water and stores and eliminates undigested foods. Large intestine: 5 major portions: o Ascending colon o Transverse colon o Descending colon o Sigmoid colon o Rectum. The opening for defecation (expelling stool) is the anus. Small Intestine 3: DJiL = o Duodenum, o Jejunum o Ileum. Urinary System: - Consists of: o Two Kidneys ▪ Kidneys filter the blood. ▪ Functional units of the kidneys Nephrons. ▪ Water, glucose, and ions leave the nephrons by diffusion and reenter the blood. o Two Ureters ▪ The ureters are tubes that transport urine to the urinary bladder where urine is stored before urination through the urethra to the outside. o Urinary Bladder o The Urethra - Filtration process: is occurring in the glomerulus in the Bowman ’s capsule under the force of blood pressure. - Reproductive system: Male and female sex organs include testes and ovaries. o Testes and ovaries have two functions: 1. Production of gametes (sex cells) 2. Production of hormones. - These activities are under control of the TROPIC HORMONES from the pituitary gland. These gametes are formed by meiosis. Male reproduction: o Spermatozoa develop within the seminiferous tubules of each testis. o Interstitial cells between the seminiferous tubules produce testosterone. o Testosterone influences sperm cell development and produces the male secondary sex characteristics such as increased facial hair and body hair as well as voice deepening. o Sperm are stored in the epididymis of each testis. o Pathway of ejaculation includes: vas deferens, prostate gland, and bulbourethral gland (Cowper’s gland). - Anterior Pituitary Gland: Testicular activity is under control of two hormones. FSH (follicle stimulating hormone) regulates sperm production and ICSH (interstitial cell-stimulating hormone or LH stimulates the interstitial cells to produce hormones. Female reproduction: o FSH – several eggs ripen within the ovarian follicles of the ovary. o Estrogen produced by the follicle initiates preparation of endometrium of the unterus for pregnancy. o Day 14 of cycle, a surge of LH is released from the pituitary gland, which stimulates ovulation and the conversion of the follicle to corpus luteum. o Progesterone and Estrogen - Which further stimulate development of the endometrium. o If fertilization occurs the corpus luteum remains the same and if it does not occur the corpus luteum degenerates, then menstruation begins.