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Sec 2 Biology

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dejahisa's version from 2017-03-26 08:29

Section 1

Question Answer
What is diffusion?NET MOVEMENT OF PARTICLES from a region of HIGHER CONCENTRATION to a region of LOWER CONCENTRATION
Particles continue to diffuse until ..?concentration of particles is uniform throughout & until it reach an EQUILIBRIUM
Name the 5 factors affecting rate of diffusionConcentration gradient (steeper, faster); Size of particles(smaller, faster), Temperature(higher, faster); Thickness of barrier (thinner, faster); Surface area to vol. ration (larger, faster)
What is the function of root hair?To INCREASE SURFACE AREA TO VOLUME RATIO to absorb the WATER & MINERAL SALTS
What is osmosis?Movement of WATER MOLECULES from a region of HIGHER WATER POTENTIAL to a solution of LOWER WATER POTENTIAL through a PARTIALLY PERMEABLE MEMBRANE
Describe what will happen to an animal cell in a hypertonic solutionThe water would ENTERthe cell, causing it to EXPAND and BURST
Describe what will happen to an animal cell in a hypotonic solutionWater LEAVES the cell, causing it to SHRINK in size. Little SPIKES appear on the cell membrane. The cell is CRENATED. The cell becomes DEHYDRATED and eventually dies.
Describe what will happen to a plant cell in a hypertonic solutionThe VACUOLE INCREASES in size, and PUSHES CELL CONTENTS AGAINST THE CELL WALL [TURGOR PRESSURE]. The strong and inelastic cell wall exerts an OPPOSING FORCE. This prevents the OVER-EXPANSION OF CELLS; ENTRY OF MORE WATER; CELL FROM BURSTING. The cell is turgid.
Describe what will happen to a plant cell in a hypotonic solutionVACUOLE DECREASES in size, CYTOPLASM SHRINKS FROM CELL WALL and the cell is PLASMOLYSED. This causes the plant to be FLACCID. If plant CELLS are PLASMOLYSED for too long, the PLANT starts to wilt and eventually dies.
What is active transport?A process in which ENERGY IS USED to MOVE PARTICLES of a substance AGAINST a concentration gradient from a region of LOWER CONCENTRATION to a region of HIGHER CONCENTRATION
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Section 2

Question Answer
What are the 6 characteristics of an artery?Thick, elastic wall; carries oxygenated blood except pulmonary artery; carry blood away from heart; lumen is small; valves are absent, blood flows under great pressure & high speed
What are the 6 characteristics of a vein?Thin, inelastic wall, carries deoxygenated blood except pulmonary vein; carry blood towards the heart, lumen is big, valves are present, blood flow is smooth and slow
What are the 3 characteristics of a red blood cell?Biconcave; Function: To carry oxygen gas around human body; nucleus is absent
What are the 3 characteristics of a white blood cell?Larger and rounder; Function: To fight against bacteria and foreign bodies entering body; nucleus is present
What is the function of platelets?To help blood clot
What is plasma made up of?Water and dissolved substances including nutrients & waste substances
What are the 2 characteristics of phloem tube? (function & what it's made up of)It carries MANUFACTURED CARBOHYDRATES in the form of sugar, from leaves to every part of the plant; Made of living cells and have thin walls
What are the 2 characteristics of xylem tube? (function & what it's made up of)Carries water and dissolved minerals from roots to all parts of plant; Made of dead cells and thick walls
How does the xylem tube serve as mechanical support?Make plant stand upright due to presence of thick walls; deposit of lignin on inner surface of xylem tube
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Section 3

Question Answer
What is the digestive equation for digestion taking place in the mouth?Starch -----salivary amylase------------> Maltose
What is the digestive equation for digestion of maltose?Maltose ----------(maltase)--------------> glucose
What is the digestive equation for digestion in the stomach?Protein --------(protease)----------> simpler proteins
What is the digestive equation for digestion of simpler proteins?Simpler proteins ---------(protease)-------------> amino acids
What is the digestive equation for digestion of fats?Fats ------(pancreatic & intestinal lipase)----------> glycerol and fatty acids
What happens to an enzyme when it is placed in a temp too low?It will be inactive. It posesses little K.E. --> frequency of enzymes colliding with substrate is low
What happens to an enzyme when it is placed in a temp too high?It will be denatured. Enzymes unable to catalyse any further as shape of enzyme is changed and active site is lost
Bile is made in _____________ but stored in _____________.Liver; gall bladder
Function of bile?Breaks fats into small flat globules which makes them easier to digest
What happens if the Gall bladder is removed?It stores bile juice temporarily. DIGESTION OF FATS IS AFFECTED if it's removed. As bile juice helps in BREAKING DOWN THE FATS INTO SMALLER FAT GLOBULES OR EMULSIFYING THE FATS. This is to INCREASE THE SURFACE AREA for the digestion of fats by enzymes PANCREATIC LIPASE AND INTESTINAL LIPASE
Name 3 ways in which absorption of food is made easier.Presence of villi (increase SA to vol. ratio, increase rate of absorption); Wall of small intestine one-cell thick, shortens distance between wall and blood vessels); Small intestine is long, increase SA to vol. ratio
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Question Answer
What are the 4 characteristics of sperm?Has flagella; smallest cell in male body; produced in testes; able to move
What are the 4 characteristics of ovum?No flagella; largest cell in the female body; produced in ovaries; not able to move
What is the function of a placenta?It serves as a platform for the exchange of substances - it allows the diffusion of oxygen, nutrients and water from the mother to the foetus (does NOT transport)
What are the symptoms of gonorrhea?pain when urinating; thick liquid (pus) coming out of penis/vagina; damages reproductive organs leading to sterility; may cause blindness in babies born from mothers with disease
What are the symptoms of syphillis?Early stages(sores on mouth & reproductive organs); Late stages(deformed joints, abnormal teeth, serious heart & brain problems, insanity, babies born from mother with disease are blind, deaf or dead)
What are the symptoms of AIDS?Fatigue; weight loss; fever; serious diarrhoea; enlarged nymph nodes; sores in mouth, nose or anus; shortness of breath
What is menstruation?The discharge of dead ovum, broken uterus lining and blood
When does ovulation occurOn the 14th day
Name 2 characteristics of ligation (presuming this is a difference question)Female permanent contraceptive method; Cutting & Tying of oviduct
Name 2 characteristics of vasectomy (presuming this is a difference question)Male permanent contraceptive method; Cutting & tying of sperm duct
Why is IUD a method of abortion?Contraception or birth-control is to prevent fertilisation. However, IUD does not prevent fertilisation from occurring. Its working principle is to prevent the implantation of zygote to the wall of the uterus. Hence, it is considered as abortion or deliberate ending of pregnancy.
Name 3 ways to prevent AIDS.Having sexual intercourse with 1 uninfected partner & avoiding promiscuous sexual behaviour; Having sexual intercourse using condom; Not taking drugs & sharing of instruments that are less likely to break the skin & be contaminated with blood
Function of condom?Prevents any sperm from being deposited in vagina
Function of birth-control pillsPrevent pregnancy by stopping ovulation
Function of cap & diaphragmPrevent sperm from entering uterus
Function of spermicidesContain substances that kill sperms
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