Science Q1.pdf

Science Reviewer Respiratory System Breathing is the process that delivers oxygen to where it is needed in the body and removes carbon dioxide. We breathe in to allow oxygen to move into our bloodstream and we breathe out to remove carbon dioxide from our blood....

Science Reviewer Respiratory System Breathing is the process that delivers oxygen to where it is needed in the body and removes carbon dioxide. We breathe in to allow oxygen to move into our bloodstream and we breathe out to remove carbon dioxide from our blood. The oxygen is carried in the blood to all cells of the body. nose and mouth (nasal cavity) The nose is what we normally use to inhale and exhale. It has two holes called nostrils through which air passes. The skin lining both nostrils is embedded with tiny hairs called cilia, which act like a filter to catch dust and other small particles in the air we breathe. pharynx and larynx (throat & voice box) Both food and air pass through the pharynx ; it is lined with tissues called tonsils which can partially obstruct the passage of either of the two. Like when swallowing, respiration is interrupted. The pharynx ends in the esophagus and the larynx. The larynx houses vocal chords and the different muscles used in producing sounds. The epiglottis, a cartilage found at the top of the larynx, aids in closing it tightly to prevent the passage of food or liquids. trachea and bronchi The trachea or also referred as the “windpipe”, is a tube through which respiratory gas transport takes place. It is lined with ciliated cells to push particles out, and cartilage rings to guard it against pressure when breathing. The end of the trachea split into two tubes called the bronchi, which also have several thin-walled branches called bronchioles. These bronchioles lead to air sacs called alveoli, where most of the gas exchange happens. lungs They consist of a cluster of bronchioles and alveoli, blood vessels, and elastic tissue. Their main function is to transfer oxygen into the bloodstream, and to excrete carbon dioxide into the air. Mechanism of Breathing - Inhalation (inspiration) and exhalation (expiration) are the processes by which the body takes in oxygen and expels carbon dioxide during breathing. You breathe with the help of the diaphragm and the intercostal muscle between your ribs.  - The diaphragm is shaped like a parachute and located below your lungs. It divides the chest cavity from the abdomen, while intercostal muscles are located between your ribs. Breathing in (Inhalation) - when you breathe in (inhale), your diaphragm contracts (tightens) and moves downward. In this way, it could provide a bigger space for your lungs to expand in the chest cavity. Also, the intercostal muscles help widen the area in the chest cavity. - They contract to pull your rib cage both upward and outward when you breathe. As your lungs expand, air enters the nose and mouth, travelling towards your windpipe and into your lungs. Breathing out (Exhalation) - when you breathe out (exhale), your diaphragm relaxes and moves upward into the chest cavity. The intercostal muscles also relax to decrease the area in the chest cavity. As the space in the chest cavity reduces, carbon dioxide is pushed out of your lungs and windpipe, and then out of your nose or mouth. Diseases of the Respiratory System 1. Asthma - a common, continuing respiratory condition that causes difficulty breathing due to inflammation of the airways. 2. Chronic Obstructive Pulmonary Disease (COPD) - the development of sputum makes the infected suffer from difficulty in breathing. 3. Chronic Bronchitis - a disease that makes the bronchial tubes swell. 4. Emphysema - another form of COPD that causes damage to the air sacs in the lungs or alveoli. 5. Lung Cancer - bumps are shaped in the lungs that cause cancer 6. Tuberculosis - mycobacterium targets the lungs and damages the other parts of the body. 7. Pneumonia - the. swelling of alveoli is caused by virus, bacteria, or fungi. 8. Coronavirus Disease (COVID-19) - this new disease comes from a type of coronavirus named SARS-COV-2. Symptoms show up to 14 days. Some are asymptomatic that no symptoms show, but they are already infected and can spread the virus if not in isolation. Circulatory System The function of the circulatory system is to transport oxygen and nutrients to the body cells and to carry deoxygenated (oxygen-poor) blood and carbon dioxide back to the heart and lungs. Its major parts are the heart, the blood, and the blood vessels. The heart is a muscular pump which keeps the blood flowing to each part of the body. The blood circulates through a closed system—that is, blood in the circulatory system stays inside the vessels Blood : Fluid Transport - Blood is a tissue made of fluid, cells, and fragments of cells. The fluid or the flowing portion of the blood is termed plasma. Plasma is a straw-colored fluid and makes up about 55% of the total volume of blood. Red and white blood cells and platelets are suspended in plasma. Blood Vessels : Pathways of Circulation Arteries carry blood away from the heart towards the rest of the body. They carry oxygenated blood (oxygen-rich) blood except pulmonary arteries, which carry deoxygenated blood to the lungs for oxygenation. The arteries branch off from the heart. They branch off into smaller arteries called arterioles. Veins carry blood from the rest of the body back towards the heart. They carry deoxygenated (oxygen-poor) blood excluding pulmonary veins, which carry oxygenated blood from the lungs to the heart. In your body, oxygen-poor blood has a darker red color. - You can think of arteries and veins as a system of roads. Large arteries and veins are like major highways. Smaller arteries and veins are like streets that route traffic through local neighbourhoods. Capillaries are the smallest blood vessels that move blood to and from the cells of the hody. These vessels are so small that blood cells must move through them in single file. Its walls are very thin that materials can easily diffuse into and out of them. It carries both oxygenated and deoxygenated blood. Heart : The Vital Pump The main function of the heart is to keep blood moving constantly through the body. The largest structures in your heart are the four chambers. The two smaller chambers are the right atrium and left atrium (plural, atria), and two larger chambers are the right and left ventricles. The ventricles are separated by a thick wall of tissue called septum. The heart valves are flaps of tissue that prevent blood from flowing backwards. They open when the atria or ventricles contract, and shut when it relaxes. Types of Circulation 1. Pulmonary Circulation - occurs only between the heart and the lungs, the main function of this circulation is to carry deoxygenated (oxygen-poor) blood to the lungs, where it picks up O2, expels excess CO2 and water, and carries oxygenated (oxygen-rich) blood back to the heart.  2. Systemic Circulation - occurs between the heart and the rest of the body, except for the lungs. The main function of this circulation is to carry oxygenated blood to all cells and transport deoxygenated blood back up to the heart. Systemic circulation starts when blood leaves the ventricle. 3. Coronary Circulation - consists of the blood vessels that supply blood to, and remove blood from, the heart. The vessels that provide blood high in oxygen levels to the heart are called coronary arteries. Diseases of the Circulatory System 1. Atherosclerosis/Arteriosclerosis - makes the arteries hard caused by high consumption of a fatty diet that leaves fat deposits on the lining of the blood vessels. These fat deposits make the arteries rigid. 2. Heart Attack - is caused when the heart is blocked from blood supply due to a blood clot. 3. Myocardial ischemia - the buildup of fat deposits congests the blood flow to the heart 4. High cholesterol - cholesterol-rich food excessive consumption may lead to hypertension 5. Heart Failure - the unstable behaviour of the heart cannot pump sufficient blood for the body's needs. 6. Stroke - can happen if a vessel that supplies blood to the brain either becomes blocked by a blood clot or bursts these stop blood flow and prevent oxygen from getting to the brain. 7. High Blood Pressure (Hypertension) - the elevation of blood pressure in the vessels gets too high that it can trigger other diseases. 8. Anemia - the insufficient supply of red blood cells in the blood can make you feel easily tired. Laws of Mendelian Inheritance 1) Law of Dominance - states that in a heterozygous condition, the allele whose characters are expressed over the other allele is called dominant allele and the characters of this dominant allele are called dominant characters. The characters that appear in the Family 1 (F1) generation are called dominant characters. The recessive characters appear in the Family 2 (F2) generation. 2) Law of Segregation - states that when two traits come together in one hybrid pair, the two characters do not mix with each other and are independent of each other. Each gamete receives one of the two alleles during meiosis of the chromosome.  3) Law of Independent Assortment - this means that at the time of gamete formation, the two genes segregate independently of each other as well as of other traits. Law of independent assortment emphasizes that there are separate genes for separate traits and characters and they influence a d sort themselves independently of the other genes. A Punnett Square, named after Reginald Punnet who devised the approach, is useful in predicting phenotypes/genotypes of offspring from a given cross. Phenotype - the outward appearance of an individual or organism/the physical expression of a trait. ex : tall, short Genotype - the genetic makeup of an individual represented by letters Homozygous - having the same allele. ex : TT (homozygous tall) or tt (homozygous short) Heterozygous - having different alleles. ex : Tt (heterozygous tall) Dihybrid Cross : Non-Mendelian Patterns of Inheritance Incomplete dominance is a case of inheritance where the heterozygous phenotype shows a blend of the dominant and recessive alleles, resulting in an intermediate phenotype. This occurs when the dominant allele is unable to entirely dominate or does not completely mask the recessive allele. Since the intermediary phenotype is essentially a combination of a dominant and recessive genes, incomplete dominance is also known as partial dominance or semi-dominance Codominance is a type of inheritance where both alleles for the trait are expressed in heterozygote at the same time. With codominance, a cross between, a cross between organisms with two different phenotypes produces offspring with a third phenotype in which both parental traits appear together. This means that both alleles contribute to the phenotype. In this case, alleles are neither dominant nor recessive. Multiple Alleles sometimes, even if only two alleles control a trait, there may be more than two types of alleles available. This will also lead to more than two phenotypes expressed. An example of multiple allelism is the inheritance of human ABO blood types : A, B, AB, O. What are alleles? Alleles are a pair of genes, occupying a specific location in a chromosome called locus (plural, loci) and control the same trait. One member of a pair is called allele, an alternative form of a gene. All the alleles found in an organism make up the genotype. Phenotype (Blood Type) Genotypes/s Description of Genotype A IAIA Homozygous dominant for blood type A IAi Heterozygous for blood type A B IBIB Homozygous dominant for blood type B IBi Heterozygous for blood type B AB IAIB Codominant for blood type AB O ii Homozygous recessive for blood type O  It tells us the alleles for IA and IB are dominant over the i allele, which is always recessive. However, when the IA and IB alleles are inherited together, both alleles are expressed equally, and are codominant of each other. What determines blood type? The blood type is determined by the presence or absence of specific immunoglobulin, a protein that serves as an antigen on the surface of the red blood cells (RBCs). Antigens are identification markers that protrude from the surface of the RBCs. Allele IA directs the synthesis of antigen A, allele IB directs the synthesis of antigen B and i does not produce antigen. What blood type can I receive or donate? Blood plasma contains antibodies (proteins produced by white blood cells as part of immune defense). Plasma antibodies of the blood do not bind to their own red blood cell antigen. This means, anitegn A does not bind to antibody B, antigen B does not bind to antibody A. If antibodies in the blood plasma bind to red blood cell antigens, the red blood cells clump together. Sex linked trait is a trait controlled by the genes found in the sex chromosomes. Genes located on the X chromosomes are called X-linked genes and while genes located on the Y chromosomes are Y-linked genes. Genese in the X or Y chromosomes are sex linked because their expression and inheritance patterns differ between males or females. Hypertrichosis pinnae auris, is a genetic disorder in humans that causes hairy ears. It is an example of a Y-linked trait. So, if a father has this trait, all his sons will inherit the gene. Sex-influenced trait is controlled by genes found in body chromosomes. It is expressed both in male and female but is often more frequent in one than in the other sex. This expression is governed by sex hormones. ex : Baldness is more commonly expressed in males. Even a female has an allele for being bald but it will never be expressed unless both of her chromosomes have genes for baldness. This is because men have a higher level of testosterone than women. Thus, in men, baldness appears to be dominant while recessive in females. Sex-limited trait is exclusively expressed in one sex of the species. ex : In cattle, lactation is expressed in females but never in males. Both male and female cattle however possess a gene pair for lactation. The gene for lactation (L) is dominant over the nonlactating gene (l). Milk production involves interaction of different hormones during pregnancy. Life Energy : Photosynthesis and Cellular Respiration How do organisms obtain energy? Autotrophs like plants, algae, cyanobacteria are organisms capable of producing their own food like plants, algae and cyanobacteria. They use sunlight, water, and carbon dioxide to make their own food (sugar) in a process called photosynthesis. Heterotrophs like animals, fungi and some bacteria cannot make their own food so they use the food (sugar) produced by the autotrophs for their energy needs in a process called cellular respiration What is photosynthesis? Photosynthesis is a process of food making among autotrophs. The presence of chlorophyll enables light energy, carbon dioxide (CO2) and water (H20) to make food (sugar). Below is the chemical reaction for photosynthesis: What structures are involved in the food making process in plants? In plants, photosynthesis primarily takes place in the leaves and in some parts of the plants with chlorophyll Chlorophyll is the green pigment of the plants which traps light energy and converts it into chemical energy during photosynthesis. Mesophyll is the part of the leaf which has the greatest number of chloroplasts, an organelle containing chlorophyll. Vascular bundles composed of xylem and phloem are the transporting vessels of the plants. The xylem transports water and minerals while the phloem transports food (sugar). Stomates are microscopic pores or openings in the epidermis of the leaves which allows exchange of gases (carbon dioxide, oxygen and water vapor). Guard cells regulate the opening and closing of stomates. What is inside the chloroplast? In all autotrophic eukaryotes, photosynthesis takes place inside an organelle called a chloroplast. For plants, chloroplast- containing cells exist in the mesophyll. Chloroplasts have a double membrane envelope composed of an outer membrane and an inner membrane. Within the double membrane are stacked, disc-shaped structures called thylakoids. A stack of thylakoid is called a granum, and the liquid- filled space surrounding the granum is called stroma. Embedded in the thylakoid membrane is chlorophyll. 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. The green light, on the other hand, is reflected thus making chlorophyll look green. What are the two stages of Photosynthesis? 1. Light-dependent reaction takes place within the thylakoid membrane and requires a steady stream of sunlight. The chlorophyll absorbs energy from the light waves which is converted into 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 2. The light-independent reaction or Calvin cycle takes place in the stroma, the space between the thylakoid membranes and the chloroplast membranes, and does not require tightness. During this stage, energy from the ATP and NADPH molecules is used to carbohydrate molecules, like glucose, from carbon dioxide. What are the factors affecting the rate of photosynthesis? The factors affecting the rate of photosynthesis are temperature, carbon dioxide, water and light. Providing the plant with the right amount of these materials will ensure good quality and quantity of harvest