Grade 9 Science Reviewer Quarter 1 (PDF)

Grade 9 Science Reviewer Quarter 1 Q1: Living Things and Their Environment UNIT 1: Respiratory and Circulatory Sytems I. Respiratory and Circulatory Systems The respiratory system is made up of organs that enables us to breathe Circulatory system is resp...

Grade 9 Science Reviewer Quarter 1 Q1: Living Things and Their Environment UNIT 1: Respiratory and Circulatory Sytems I. Respiratory and Circulatory Systems The respiratory system is made up of organs that enables us to breathe Circulatory system is responsible for distributing materials/nutrients throughout the body Just take note respiration is linked to breathing They share a common responsibility with supplying nutrients in our body. The common purpose of these two systems could not be attained without the other system. The Human Breathing System: In charge of supplying oxygen; nose, nasal passageways, windpipe and diaphragm. The entering air is made up of warm, damp and clean of unknown particles. Next, the air moves down through the; trachea, bronchi, bronchioles and alveoli. The respiratory system performs two major tasks: Exchanging air between the body and the outside environment known as external respiration. Bringing oxygen to the cells and removing carbon dioxide from them referred to as internal respiration. Organs of the Respiratory System: Nose – also called external nares Divided into two halves by the nasal septum. Contains the paranasal sinuses where air is warmed. Contains cilia which is responsible for filtering out foreign bodies. Pharynx – also known as the throat, it is a passageway for both air and food. Three Sections of the Pharynx Nasopharynx – contains the adenoids which aid in the body’s immune defense.  Oropharynx – back portion of the mouth that contains the palatine tonsils which also aid in the body’s immune defense. Laryngopharynx – bottom section of the pharynx where the respiratory tract divides into the esophagus and the larynx. - The epiglottis, a movable flap of cartilage that covers the opening of the larynx (voice box) prevents food from entering the larynx during swallowing. - Occasionally, a person may swallow and inhale at the same time so some food may enter the larynx and choking occurs. A technique called Heimlich maneuver has saved many people from choking to death. Larynx – serves as a passageway to the trachea and the area where sounds are produced. Size and thickness determine the pitch of the sound. - Short and thin = high pitch - Thick and long = low pitch Larynx Trachea Trachea – also known as the windpipe, connects the larynx to the right and left bronchi, point at which it divides into the right and left bronchi is called the Bronchi mediastinum. Internal Respiration – Air from the bronchi travels to the bronchioles, then to the alveoli which connect to lung capillaries. Oxygen and Carbon dioxide are exchanged and oxygen is delivered to the body cells. Lungs – consists of a right and left lobe, covered by a double layer of membrane that makes movement in the thoracic cavity easier. The outer layer is parietal pleura and the inner layer is the visceral pleura. The space between the two pleurae is called pleural cavity. Consists of an apex(top section), hilum(middle section) and base(lower section) The passage of air from the external environment to the lung capillaries, bloodstream and out consists of one inhalation and one exhalation.  II. The Circulatory System The circulatory system is the life support structure that nourishes your cells with nutrients from the food you eat and oxygen from the air you breathe. Another name for the circulatory system is the cardiovascular system. It circulates vital elements such as oxygen and nutrients. At the same time, it also transports wastes away from the body. Take note that circulation means the transportation or movement in circles. Functions of the Circulatory System: Transporting substances around the body. These include oxygen, glucose, carbon dioxide, nutrients, water and waste products Controlling body temperature. Protecting the body. Blood contains cells and anti-bodies that fight infection and clotting agents to stop bleeding. Parts of the Circulatory System: Heart – pumps the blood throughout the body. Cardiac System – The four right left chambers of the heart atrium An upper chamber is called an atrium atrium (right atrium and left atrium) right left A lower chamber is called a ventricle ventricle ventricle The walls are made of cardiac muscle The semi-lunar valves prevent expelled blood flowing back into the heart. The wall dividing the left and right sides of the heart is called the septum. Two valves (bicuspid (mitral) and tricuspid) prevent blood flowing back into the atria from the ventricles. Stroke volume is the amount of blood pumped out of the left ventricle per beat. Cardiac output is the amount of blood pumped out of the left ventricle of the heart per minute. Cardiac output can be calculated by multiplying the stroke volume by the heart rate: cardiac output = stroke volume × heart rate Heart rate/pulse rate – is the number of times your heart beats every minute. It is expressed in beats per minute (BPM). The fitter you are, the lower your resting heart rate will be.  Average resting heart rate = 70-75 BPM Estimation of using a simple formula: Maximum Heart Rate (MHR) = 220 – age To keep the body supplied with what it needs, the hearts beats faster and with greater force. This means the heart rate and stroke volume increase. Regular exercise causes changes to the heart - The heart gets larger - The muscular wall become thicker and stronger - Stroke volume at rest increases leading to a lower resting heart rate Blood Vessel – carries the blood throughout the body. - Arteries – carries oxygenated blood away from the heart to the cells, tissues, and organs of the body. - Veins – carry deoxygenated blood to the heart. - Capillaries –the smallest blood vessels in the body, connecting the smallest arteries to the smallest veins. the actual site where gases and nutrients get exchanged. Blood vessels: Valves When blood is flowing against gravity, or when a vein is squeezed by muscle action, there is a risk that blood will flow in the wrong direction. Veins have valves to prevent backflow. Blood pressure depends on the speed of the blood coming into a vessel and the width of the vessel itself. Arteries Capillaries Veins Speed: High Speed: Medium Speed: Low Width: medium Width: narrow Width: Wide Pressure: High Pressure: Medium Pressure: Low An individuals blood pressure is affected by a number of factors: Age – it increases as you get older. Gender – men tend to have higher blood pressure than women. Stress – can cause increased blood pressure. Diet – salt and saturated fats increase blood pressure. Exercise – the fitter you are the lower your blood pressure is likely to be Having High blood pressure puts stress on your heart. It can lead to; Angina, heart attacks and strokes.  Blood – carries the materials throughout the body. Transports oxygen from the lungs to the heart and then body to the tissues, Carbon dioxide from the tissues to the heart and then to the lungs to be expired, materials like hormones from one organ to another, nutrients especially glucose and minerals from the intestines to the tissues, and waste products to the kidneys. Red blood cells - also called erythrocytes, it is disc shaped, contains a red colored compound called hemoglobin which bonds with oxygen to form oxyhemoglobin. It transports oxygen to the tissues. White blood cells – also called leucocytes, they are bigger than red blood cells and have larger nuclei, it acts as the body’s defense system. Some white blood cells surround and consume harmful microbes, they are also responsible in producing antibodies that fight infection Platelets – are also carried in the blood, formed in the red bone marrow, they produce thrombokinase; a chemical needed for blood clotting. Platelets help to repair tissues and close wounds both internally and externally. When needed they grow into irregular shapes and stick together to form a plug over the wound. Plasma – the blood cells and platelets are suspended in a substance called plasma. Plasma is made up of; - 90% water - Inorganic salts - Glucose - antibodies - urea and other waste products - plasma proteins Plasma can be separated from the other components of the blood using a centrifuge. The Circulatory System: - Deoxygenated blood is pumped from the lung heart to the lungs through the s pulmonary artery. - Deoxygenated blood returns to the heart through the vena cava - Oxygenated blood returns to the heart through the pulmonary vein. - Oxygenated blood is pumped at high pressure from the heart to the body through the aorta. body’s cells  III. Pathology of the Respiratory and Circulatory System Upper respiratory infection is a term that covers an infection of some or all the of the respiratory tract Chronic Obstructive Pulmonary Disease (COPD) is a term for any disease with chronic obstruction of the bronchial tubes and lungs such as: - Emphysema - Chronic Bronchitis Asthma - causes narrowing of the bronchi leading to dyspnea, wheezing, and coughing. Hemoptysis - lung or bronchial hemorrhage that results in spitting of blood Cystic Fibrosis - disease of the exocrine glands that causes secretion of abnormally thick mucus which leads to chronic obstruction. Atelectasis - collapsed alveoli leading to a collapse of a lung or part of a lung. Pneumonia – acute infection of the alveoli. Conditions caused by environmental agents; Pneumoconiosis – caused by dust in the lungs Anthracosis – caused by coal dust Asbestosis – caused by asbestos particles released during construction of ships and buildings Silicosis – caused by silica dust from grinding rocks or glass Disorders of the Pleura Pneumothorax – accumulation of air or gas in the pleural cavity Empyema – pus in the pleural cavity Hemothorax – blood in the pleural cavity Pleural Effusion – escape of fluid into the pleural cavity IV. Surgical Terms Otorhinolaryngologists – are physicians that specialize in disorders of the upper respiratory tract. Surgical Removal Conditions - Tonsillectomy - Laryngectomy - Adenoidectomy - Pneumonectomy - Lobectomy Surgical Incisions - Laryngotracheotomy - Sinusotomy - Thoracotomy - Tracheotomy  Endotracheal intubation is the insertion of a tube through the nose or mouth, pharynx, larynx, and into the trachea to establish an airway. V. Pharmacology Antibiotics, antihistamines, and anticoagulants are used for respiratory disorders just as with other system disorders. Medications specific to Respiratory Conditions Bronchodilators – dilate the bronchial walls Expectorants – promote coughing and expulsion of mucus Mechanical Devices that aid in Respiration Ventilators – serves as a breathing substitute to patients who cannot breathe on their own. Nebulizers – deliver medication through the mouth or nose to ease breathing problems Agents used to treat respiratory conditions Antitussive – relieves coughing Decongestants – decreases and prevents mucus buildup Expectorants – promotes coughing and expelling of mucus UNIT II: Heredity and Inheritance and Variation I. Difference of Non-Mendelian and Mendelian Inheritance Gregor Mendel’s principles form the base of understanding heredity and variation. Walter Sutton and Theodore Boveri became popular because they found the best evidence that an inherited trait is determined by chromosomes. Chromosome Theory of Inheritance explained that genes are in the chromosomes. Mendelian laws of inheritance have important exceptions to them. For example, not all genes show simple patterns of dominant and recessive alleles. In the mendelian patterns of inheritance, the effects of the recessive gene are not observed when the dominant gene is present. II. Hereditary, Inheritance, and Variation Allele – a different form of a gene that controls a certain trait Punnett Square – the method of which one can determine the possible genotypes and phenotypes when two parents are crossed Gamete – are reproductive cells that unite during sexual reproduction to form a new cell called a zygote.  Incomplete Dominance - a heterozygote shows a phenotype that is intermediate between the two homozygous phenotypes. Neither allele is dominant over the other. EX. Red Flower (RR) R R Crossed between White Flower (WW) W RW RW W RW RW Key Concepts: Incomplete dominance is a form of intermediate inheritance in which one allele for a specific trait is not completely dominant over the other allele. This results in a third phenotype in which the expressed physical trait is a combination of the dominant and recessive phenotypes. Codominance - this results when one allele is not dominant over the other. The resulting heterozygotes exhibit the traits of both parents. Ex. M Blood Type (LMLM) crossed between Lm Ln MN Blood Type (LMLN) Lm LMLM LMLN Lm LMLM LMLN Key Concepts: In codominance, both alleles are expressed equally in the phenotype of the heterozygote. For example, red cows crossed with white cows will have offspring that are roan cows. Roan refers Multiple Alleles - even if only two alleles control a trait, there may actually be more than two types of alleles available. This will also lead to more than two phenotypes expressed. An example of this is the Human ABO blood types and their phenotypes. Blood Types Genotypes A IA IA, IA i B IB IB, IB i AB IA IB O ii The IA and IB alleles are dominant over the i alleles, which is always recessive. However, when the IA and IB alleles are inherited together, both alleles are expressed equally. This makes IA and IB codominants of each other.  Sex Chromosomes and Sex Determination - Humans have 46 chromosomes in each cell Observation of the human body cell shows 23 pairs of chromosomes for both males and females. 22 pairs are somatic chromosomes. The 23rd pair consists of sex chromosomes. Male Chromosome (XY) Female Chromosome (XX) Key Concepts: Males have 44 body chromosomes and two sex chromosomes X and Y. Males = XY Chromosomes The males determine the sex of their children. Females Have 44 body chromosomes and two sex chromosomes, both X Females = XX Chromosomes The total number in each cell of an individual is 46. These chromosomes contain the genes, which are the factors of heredity. Sex-Linked Genes Genes located on the X chromosomes are called X-Linked Genes. Genes on the Y chromosomes are called Y-Linked Genes Genotype Phenotype -Ex. Genotypes and XX Normal Female phenotypes of color blindness in humans X XC Normal Female, carrier of the gene XC XC Color-blind female XY Normal male XC Y Color-blind male Key Concepts: - Sex-linked traits are inherited through the X chromosomes. - Males have only one X chromosome. Thus, if they inherit the affected X chromosome, they will have the disorder. - Females have two X chromosomes. Therefore, they can inherit/carry the trait without being affected if it acts in a recessive manner Sex-Limited Traits - are generally autosomal. Which means that they are not found on the X or Y chromosomes. Female Female Phenotype Genotype Ex. Expression of lactation XXLL Female Lactating in cattle XXLl Female Lactating XXll Female not lactating Male Male Phenotype Genotype XYLL Male not lactating XYLl Male not lactating XYll Male not lactating Sex-Influenced Traits - are also autosomal, it means that their genes are not carried on to the sex chromosomes. One example of sex influenced trait is pattern baldness in humans, though the condition is not restricted to males. Female Female Phenotype Genotype XXBB Female Bald XXBb Female nonbald Ex. Expression of pattern XXbb Female nonbald baldness in humans. Male Male Phenotype Genotype XYBB Male bald XYBb Male bald XYbb Male nonbald Key Concepts: - Sex limited traits are those that are expressed exclusively in one sex - Sex influenced traits are expressed in both sexes but more frequently in one than in the other sex.  III. DNA: The Genetic Material - The genetic materials, also known as the deoxyribonucleic acid or DNA, are passed on from one generation to the next to ensure continuity of life. - By the end of 1940, scientists had found that DNA consists of long strands of nucleotides; DNA is composed of chains of nucleotides built on a sugar and phosphate backbone and wrapped around each other in the form of a double helix. Each nucleotide contains a pentose sugar called deoxyribose, a phosphate group, and one of the four compounds called nitrogenous bases; The backbone supports four bases: Adenine Thymine Guanine Cytosine UNIT III: Biodiversity and Evolution Different parts of the ecosystem interact with one another. Changes to one part affect other parts. When all members of a species die, that species’ place in the ecosystem is gone forever. - Population is a group of living things within a certain area that are all of the same species. A population of one kind may affect a population of another kind within the community. - Biodiversity refers to the variety of life in the area. Communities with many different species (a high index of diversity) will be able to withstand environmental changes better than communities with only a few species (a low index of diversity). In a balanced ecosystem, organisms need a balanced environment. A change in population sizes may be due to factors affecting the environment When we consider the number of individuals per unit area, we are referring to density of the population. Anything that limits the size of a population like certain environmental conditions are called limiting factors. Limiting factors keep a population from increasing in size and help balance an ecosystem. Example; availability of food, water, and living conditions. The maximum population size an environment can support is called its carrying capacity. If the population size rises above the carrying capacity, organisms die because not all their needs can be met.  When a species’ population becomes so low that only a few remain, the species is considered endangered and will possibly become extinct. Examples of endangered species: Tamaraw Philippine deer Dugong Sometimes, there is a particular species that declines so fast that it becomes endangered and is said to be threatened. Human activity have resulted in habitat loss and degradation that have accelerated the rate of extinction. Deforestation – is the rapid rate at which trees are cut down. Major causes of deforestation are; - Illegal logging - Conversion of agricultural lands to housing projects - Forest fires - Typhoons As a consequence of cutting down trees, the following effects could take place; soil erosion, floods, decrease in wildlife resources. Wildlife Depletion – as human population gets bigger, huge space is needed for human development. Deforestation is one of the major causes of the disappearances of wildlife species. If wildlife species cannot find enough space, many will die or become extinct. Some species may become endangered or in the verge of becoming extinct. In other cases, some animals may be threatened. Water Pollution – a major problem in lakes, rivers and ponds is eutrophication. It happens when the concentration of organic nutrients that comes from domestic garbage are thrown in bodies of water. Effects of Eutrophication; fish kill Biological magnification is the buildup of pollutants in organisms at higher trophic levels in a food chain. Air pollution – Pollutants can enter the air as gases, liquids, or solids. Cars burn fuel and produce harmful gases-carbon dioxide, nitrogen oxides, and hydrocarbons. The trapping of heat by gases in the earth’s atmosphere is called the greenhouse effect.  Global warming is an increase in the earth’s temperature from the rapid buildup of carbon dioxide and other gases. This, in turn, could change the world climate patterns. Destruction of Coastal Resources – Coral reefs and coastal mangrove forests and nurseries of marine fishes but due to man’s activities, coastal areas are getting destroyed through the years. Some of these activities include the following; - Deforestation, agricultural activities, and mining activities - Dynamite fishing and muro-ami (fishing technique employed on coral reefs in Southeast Asia. It uses an encircling net together with pounding devices.) - Coastal areas’ conversion to beach resorts, residential areas - Overharvesting Acid Precipitation – it is commonly known as acid rain. Rainwater is normally acidic because carbon dioxide is normally present. Other pollutants, mostly sulfur and nitrogen oxides, make rainwater even more acidic with a pH of 5.6 or lower. Acid rain can be harmful to living things. It causes yellowing of leaves of trees and causes leaves to fall, aside from direct touching of leaves, nutrients can be lost from the soil. Acid water flowing through the soil can exchange acidic hydrogen ions for essential plant nutrient ions such as calcium, magnesium, and potassium. If these nutrients migrate beneath the rooting zone, they become unavailable to tree roots. UNIT IV: Ecosystem: Life Energy I. Photosynthesis is a process of food making done by plants and other autotrophic organisms. The presence of chlorophyll enables these organisms to make their own food. Autotrophic organisms require light energy, carbon dioxide (CO2), and water (H2O) to make food (sugar). Photosynthesis primarily takes place in the leaves and little or none in stems depending on the presence of chlorophyll. Plants have green pigments called chlorophyll stored in the chloroplasts The pigment aids in capturing light energy from the sun that enables plants to change it into chemical energy stored in the food.  Stomata are found on the lower surface of the leaf that allows the entrance of carbon dioxide needed for photosynthesis. They also serve as exit point for the oxygen produced during photosynthesis. Factors that affect the rate of Photosynthesis: - temperature - carbon dioxide - water - light Organisms need food as the main source of energy. All organisms need energy to perform essential life processes. The food must be digested to simple forms such as glucose, amino acids, and triglycerides. Glucose – immediate source of the cells - Glucose inside the cell is broken down to release the stored energy. - this stored energy is harvested in the form of adenosine triphosphate (ATP). ATP is a high-energy molecule needed by working cells. Glycolysis – the 6-carbon sugar, glucose, is broken down into two molecules of a 3-carbon molecule called pyruvate This change is accompanied by a net gain of 2 ATP molecules and 2 NADH molecules. Krebs Cycle – occurs in the mitochondrial matrix and generates a pool of chemical energy (ATP, NADH, and FADH2) from the oxidation of pyruvate, the end product of glycolysis Pyruvate is transported into the mitochondria and loses carbon dioxide to form acetyl-CoA, a 2-carbon molecule. When acetyl-CoA is oxidized to carbon dioxide in the Krebs Cycle, chemical energy is released and captured in the form of NADH, FADH2, and ATP. Electron Transport Chain – the electron transport chain allows the release of the large amount of chemical energy stored in reduced NAD+ (NADH) and reduced FAD (FADH2). The energy released is captured in the form of ATP (3 ATP per NADH and 2 ATP per FADH2).  The electron transport chain (ETC) consists of a series of molecules, mostly proteins, embedded in the inner mitochondrial membrane. This phase of cellular respiration produces the greatest number of chemical energy in the form of ATP. II. Parts of the Leaves Upper and lower epidermis – protects the leaves and has nothing to do with photosynthetic processes. Mesophyll – has the most number of chloroplasts that contain chlorophyll. They are important in trapping light energy from the sun. Vascular bundles – phloem and xylem serve as transporting vessels of manufactured food and water. Carbon dioxide and oxygen were collected in the spongy layer and enters and exits the leaf through the stomata. A. Parts of a chloroplast include the outer and inner membranes, intermembrane space, stroma and thylakoids stacked in grana. - The chlorophyll is built into the membranes of the thylakoids. Chlorophyll absorbs white light but it looks green because white light consists of three primary colors, red, blue and green. Only red and blue light are absorbed thus making these colors unavailable to be seen by our eyes while the green light is reflected which makes the chlorophyll look green. It is the energy from red light and blue light that are absorbed and will be used in photosynthesis III. Two Stages of Photosynthesis A. Light dependent reaction – happens in the presence of light. - It occurs in the thylakoid membrane and converts light energy to chemical energy. - Water one of the raw materials of photosynthesis is utilized during this stage and facilitates the formation of free electrons and oxygen.  - The energy harvested during this stage is stored in the form of ATP (Adenosine Triphosphate) and NADPH (Nicotinamide Adenine Dinucleotide Phosphate Hydrogen). These products will be needed in the next stage to complete photosynthetic process. B. Calvin cycle or Light independent phase – that takes place in the stroma and convert carbon dioxide (CO2) into sugar. This stage does not directly need light but needs the products of light reaction. This is why it occurs immediately after the light dependent phase. The chemical reaction for photosynthesis: Goodluck sa Exams!!