1. Microscopes
1.1. Calculating magnification
1.1.1. multiply magnification of objective lens with magnification of ocular lens
1.2. FOV
1.2.1. diameter of circle view when looking down a microscope
1.2.2. higher the magnification, smaller the FOV
1.2.3. calculate intial FOV
1.2.3.1. use tiny ruler
1.2.3.2. grid slide
1.3. Diagram of microscope
2. Cells
2.1. organelles
2.1.1. specialised structure, surrounded by its own membrane and perform specific function
2.1.2. examples
2.1.2.1. nucleus
2.1.2.2. Endoplasmic Reticulum
2.1.2.3. Chloroplast
2.1.2.4. Centrioles
2.1.2.5. Mitochondria
2.1.2.6. Vacuoles
2.1.2.7. Lysosome
2.1.2.8. Ribosome
2.1.2.9. Golgi Apparatus
2.2. non-organelles
2.2.1. cell membrane
2.2.2. Cytoplasm
2.2.3. cell wall
2.2.4. cytoskeleton
2.2.4.1. framework of protein fibres that gives cell its shape
2.2.4.2. assists in cell movement
2.2.4.3. consists of
2.2.4.3.1. microtubules
2.2.4.3.2. microfilaments
2.3. multi-cellular organism
2.3.1. can feed, excrete
2.3.2. repsire
2.3.3. respond to stimuli
2.3.4. reporudce, grow
2.4. Unicellular orgainsm
2.4.1. consists of one single cell
2.5. inclusions
2.5.1. chemical substances that are not part of the cell structure but found in cytoplasm
2.5.2. red pigment = haemoglobin
2.5.3. melanin pigment in skin, hair
2.6. cells are small
2.6.1. small cell has larger SA to volume ratio than large cell
2.6.1.1. larger SA = easier for particles to enter and leave celll
2.6.1.2. small volume = easier for organelles to reach one place from the other
3. Enzymes
3.1. metabolism
3.1.1. all chemical reactions that take place in cell
3.1.2. types
3.1.2.1. catabolism
3.1.2.1.1. reactions in which large molecules broken down into smaller ones
3.1.2.1.2. releases energy
3.1.2.2. anabolism
3.1.2.2.1. small molecules built into larger molecules
3.1.2.2.2. uses energy
3.2. importance
3.2.1. allow chem reactions to take place at body temp
3.2.2. without them- reaction proceed to slow
3.3. Specific
3.3.1. only combine with one particular subtrate
3.3.1.1. one specific chem reaction
3.4. factors
3.4.1. termperature
3.4.1.1. optimum temp
3.4.1.1.1. enzyme works best and effiicient at temp 30-35
3.4.2. Enzyme concentration
3.4.2.1. more concentrate = fast rate of chem reaction
3.4.3. Subtrate concentration
3.4.3.1. more concentrate= faster rate
3.4.4. Products of reaction must be constantly removed
3.4.4.1. or rate of reaction will slow
3.4.4.1.1. harder for subtrate mol to be in contact with enzyme mol
3.4.5. PH levels
3.4.5.1. each enzyme has optimum PH which help make more efficient
3.4.6. presence of co- factors/ co-enzymes
3.4.6.1. co-factors
3.4.6.1.1. change shape of active site so enzyme can combine with subtrate
3.4.6.1.2. certain ion
3.4.6.2. co-enzyme
3.4.6.2.1. non-protein organic molecules
3.4.6.3. most enzyme require co-factor before catalysing reaction
3.4.7. enzyme inhibitors
3.4.7.1. substances slow or stop enzyme activity
3.4.7.2. control reactions = produce products in specific amounts
3.4.7.3. penicillin inhibits enzyme in bacteria that is involved in construction of cell wall
4. Tissues
4.1. level of structural organisation
4.1.1. cell - tissues - organs - system - organism
4.2. a group of cells that are simillar in structure that work together to carry out a specific task
4.3. 4 types
4.3.1. epithelial tissue
4.3.1.1. covering or lining tissue
4.3.1.2. closely joined together
4.3.1.3. vary in shape
4.3.1.4. outer layer of skin
4.3.1.5. covering and inner lining of heart
4.3.1.6. kidneys, heart, stomach, hollow organs made up of epithelium
4.3.2. connective
4.3.2.1. provides support for body
4.3.2.2. holds all body parts together
4.3.2.3. cells not close together, separated by matrix
4.3.2.3.1. large amounts of material that is not made up of cells
4.3.2.4. bone, cartilage, tendons, ligaments, blood
4.3.3. muscular
4.3.3.1. cells are long and thin = muscle fibres
4.3.3.2. 3 types
4.3.3.2.1. skeletal
4.3.3.2.2. involuntary
4.3.3.2.3. cardiac
4.3.4. nervous
4.3.4.1. made up of specialised nerve cells (neurons)
4.3.4.2. neurons consists of long projections from the body of the cell
4.3.4.3. when neuron stimulated = messages carried along these projections from one part of the body to the other
4.3.4.4. nervous tissue found in brain, spinal cord, nerves
5. cell transport
5.1. 2 types of cell transport
5.1.1. Passive transport
5.1.1.1. cell does not use energy
5.1.1.2. Examples
5.1.1.2.1. Diffusion
5.1.1.2.2. Osmosis
5.1.1.2.3. carrier mediated transport- Facilitated Diffusion
5.1.2. Active transport
5.1.2.1. Uses energy
5.1.2.2. Examples
5.1.2.2.1. carrier mediated transport- Protein pumps
5.1.2.2.2. Vesicular transport
5.2. cell membrane
5.2.1. Plasma membrane
5.2.1.1. double layer of phospholipids
5.2.1.2. proteins floating in this layer
5.2.1.3. function
5.2.1.3.1. control entry and exit
5.2.1.3.2. seperate cell from neighbouring cells
5.3. homeostasis
5.3.1. body systems work together to make sure that cellular environment is kept constant
5.4. fluid mosaic model
5.4.1. cell membrane structure
5.4.2. 'fluid' = molecules that make up model are constantly changing position
5.4.3. 'mosaic' = all different kinds of molecules
6. Circulatory system
6.1. main internal transport system
6.2. link between cells inside body (require certain requirements) and environment outside body (supplies requirements)
6.3. special organs
6.3.1. extract requirements from environment
6.3.1.1. Digestive system = absorb nutrients
6.3.1.2. respiratory system= absorb oxygen
6.3.2. pass waste from body to environment
6.3.2.1. respiratory system = excrete CO2
6.3.2.2. Kidneys = excrete wastes
6.4. Blood
6.4.1. Transport link between cells of all the body
6.4.2. Functions
6.4.2.1. Transport O2, nutrients to all cells of body
6.4.2.2. transport CO2, other wastes products away from cells
6.4.2.3. Transport hormones to cells
6.4.2.4. maintain PH of body fluids
6.4.2.5. Distribute heat = maintain body temp
6.4.2.6. maintain water content, ion concentration of body fluids
6.4.2.7. protect against disease-causing micro-organisms
6.4.2.8. prevent blood loss = clotting when vessels damaged
6.4.3. Made of...
6.4.3.1. plasma
6.4.3.1.1. liquid part
6.4.3.1.2. 55% of blood volume
6.4.3.1.3. 91% H20
6.4.3.1.4. rest made of dissolved substances
6.4.3.2. formed elements
6.4.3.2.1. cells or cell fragments
6.4.3.2.2. 45% of blood volume
6.4.3.2.3. red blood cells (erythrocytes)
6.4.3.2.4. white blood cells (leucocytes)
6.4.3.2.5. platelets (thrombocytes)
6.5. transport of oxygen
6.5.1. 3% O2 in blood plasma
6.5.2. 97% in combination with haemoglobin molecules (red blood cells)
6.5.2.1. haemoglobin + oxygen = oxyhaemoglobin
6.5.2.1.1. Hb + O2 = HbO2
6.5.2.1.2. easily broken down to release oxygen
6.5.2.2. when O2 concentration high
6.5.2.2.1. O2 + Hb
6.5.2.2.2. occur in capillaries of lungs
6.5.2.2.3. O2 diffuses into blood from air in air sacs
6.5.2.3. when O2 concentration low
6.5.2.3.1. HbO2 = Hb + O2
6.5.2.3.2. tissue fluid around cells = low O2 concentration as cells continuously use O2
6.5.2.3.3. while flowing through capillaries between cells, red blood cells give up O2, = O2 diffuses into tissue fluid = into cell
6.6. transport of CO2
6.6.1. 3% dissolved in plasma
6.6.2. 22% as carbominohaemoglobin
6.6.2.1. combines with globin part of haemoglobin
6.6.3. 70% as bicarbonate ions
6.6.3.1. CO2 react with H20 = H2CO3 = dissociates into hydrogen ion, bicarbonate ions
6.6.4. as blood flows through capillaries between body cells, CO2 dissolves in plasma = difference in CO2 concentration
6.6.5. In alveoli (air sacs of lungs), surrounded by dense network of capillaries
6.6.5.1. CO2 dissolved in plasma = diffuses out of blood, into air in alveolus
6.6.5.2. carbominohaemoglobin breaks down = CO2 mol released, diffuses into alveolus
6.6.5.3. H ions + bicarbonate ions = form H2CO3 acid = break down under enzyme action = H20 +CO2
6.6.5.3.1. CO2 diffuses into alveolus
6.6.6. CO2 + H20 = H2CO3 = hydrogen ions + bicarbonate ions
6.7. transport of nutrients/ wastes
6.7.1. transported and dissolved in plasma
6.7.2. 4 organic nutrients
6.7.2.1. glucose
6.7.2.2. vitamins
6.7.2.3. amino acids
6.7.2.4. fatty acids / glycerol
6.7.3. 4 important ions (inorganic nutrients)
6.7.3.1. sodium ions
6.7.3.2. calcium
6.7.3.3. pottasium
6.7.3.4. chloride/ iodide
6.7.4. 3 organic wastes
6.7.4.1. urea
6.7.4.2. creatinine
6.7.4.3. urea acid
6.7.4.4. CO2
6.8. blood vessels
6.8.1. arteries
6.8.1.1. carry blood away from heart
6.8.1.2. walls smooth/eastic
6.8.1.3. divide into smaller arteries (arterioles)
6.8.1.4. arteries
6.8.1.4.1. muscles contract, reduce diameter of artery, thus, blood flow to an organ (vasoconstriction)
6.8.1.4.2. Muscle relax = increase diameter of artery = increase blood flow to organ (vasodilation)
6.8.2. capillaries
6.8.2.1. microscopic blood vessels
6.8.2.2. form network that can reach every cell
6.8.2.3. one layer of cell = easy access to surrounding cell
6.8.3. veins
6.8.3.1. carry blood back to body
6.8.3.2. no muscular walls
6.8.3.3. low blood pressure, have valves to prevent back flow
6.8.3.4. divide into smaller veins = venules
6.8.4. when exercise
6.8.4.1. cell respire = more for energy
6.8.4.2. respiration in muscle cell create wastes = CO2 and lactic acid
6.8.4.3. act as vasodilators = increase blood flow = ensure cells supplied with O2 ad nutrients
6.8.4.4. heat released increase blood temperature, increase heart rate
7. Excretery System
7.1. Removal of wastes of metabolism from body
7.2. 4 organs involved in processing and excreting wastes
7.2.1. Lungs
7.2.1.1. Excrete CO2 from body from cells
7.2.2. Liver
7.2.2.1. Process many substances so can be excreted
7.2.2.1.1. detoxifies alcohol/ drugs
7.2.2.1.2. breaks down haemoglobin to bile pigments
7.2.2.1.3. deactivates hormones
7.2.2.2. proteins
7.2.2.2.1. used extensively in body
7.2.2.2.2. built up from amino acids
7.2.2.2.3. used for cell structures, enzymes, antibodies and grandular secretion
7.2.2.2.4. very little is used in energy-releasing processes as long sufficient supply of carbohydrate/ fats
7.2.2.2.5. view protein structure
7.2.2.3. deamination
7.2.2.3.1. process of metabolising proteins to form carbohydrates
7.2.2.3.2. occurs if other energy sources used up
7.2.2.3.3. process = remove amino group (NH2) from amino acid (view diagram)
7.2.2.3.4. because amino group (NH2) converted to Ammonia (NH3) in liver (wastes)
7.2.3. Sweat Glands
7.2.3.1. lower layers of skin
7.2.3.2. Secrete sweat
7.2.3.2.1. largely water = for cooling (500 ML of water/sweat/ some drugs a day)
7.2.3.2.2. by products of metabolism = salts, urea, lactic acid
7.2.3.3. How?
7.2.3.3.1. duct carries sweat from sweat glands
7.2.3.3.2. cells surrounding glands = squeeze sweat to skin surface
7.2.3.4. view diagram
7.2.4. Kidneys
7.2.4.1. principle excretory system organs
7.2.4.2. maintain constant concentration of materials in body fluids
7.2.4.3. remove toxic wastes
7.2.4.3.1. nitrogenous wastes urea
7.2.4.3.2. uric acid
7.2.4.3.3. creatinine
7.2.4.4. review diagram
7.2.4.5. microscopic structure of kidney
7.2.4.5.1. nephron
7.2.4.5.2. urine formation
8. New Topic
9. Reproduction cycles & fertillisation
9.1. Ovarian Cycle
9.1.1. Begin at Puberty (11-14) End at menopause (40-45)
9.1.2. The cyclic changes within ovaries (28 days)
9.1.3. 3 stages
9.1.3.1. Ovulation (13-15)
9.1.3.1.1. mature follicle bursts= expels egg
9.1.3.1.2. egg swept into fallopian tubes by current (beating cilia within funnel)
9.1.3.2. Luteal phase (15-28)
9.1.3.2.1. once egg expelled = follicle collapses
9.1.3.2.2. blood within= form clots = absorbed by remaining follicle cells= corpus leteum
9.1.3.2.3. corpus luteum = secretes hormones (unfluence uterine lining)
9.1.3.2.4. 2 alternate endings
9.1.3.3. New Topic
9.2. Menstrual cycle
9.2.1. cyclic changes occuring in ovaries, where the changes in the endometrium are associated with stages in ovarian cycle
9.2.2. endometrium changes = to prepare for developing embryo (egg released at ovulation is fertillised)
9.2.3. stages- view diagram
9.3. sexual intercourse
9.3.1. in order to take place
9.3.1.1. sperm must be deposited in vagina
9.3.1.2. penis must be enlarged and firm (erection)
9.3.1.3. ejaculation must occur, can be accompanied with orgasm
9.3.1.3.1. sexual stimulation of penis = rhythmic contractions of epididymis, vasa deferentia, seminal vesicles, prostate glands propel contents of ducts and glands into urethra then out of body (3ml of semen/250-300mil sperm)
9.3.1.4. female sexually stimulated
9.3.1.4.1. blood fills erectile tissue near vaginal opening = reduce size of vaginal opening = increase stimulation of penis
9.3.1.4.2. arousal = copious secretion of mucus by glands near cervix = lubrication of epithelial lining of vagina = easy entry of penis
9.4. Fertilisation
9.4.1. male ejaculate = sperm released in vagina at entrance to the uterus ( insemination)
9.4.2. Sperm travel through cervix - body of uterus - uterine tubes
9.4.3. - upper portion of uterine tubes reached often within few minutes ( swimming motion of sperm / muscular contraction of uterus & uterine tubes
9.4.4. sperm mortality high = few thousands make out of millions make it to uterine tubes
9.4.5. since ovulation, muscular contraction of uterine tube & beating action of cilia have been transporting egg towards uterus. (fertellisation normally occur in uterine tubes, when egg 1/3 way down tube. )
9.4.6. mature egg surrounded by layer of follicle cells = corona radiata
9.4.7. acid hold cells of corona radiata together= can be loosened = thousands of sperms containing enzymnes on tip surround egg
9.4.8. entrance of 1 sperm into egg = stimulate formation of fertilisation membrane around egg = prevent entrance of anymore sperm
9.4.9. once sperm enter egg = tail absorbed, head move through cytoplasm of egg in form of male pronucleus
9.4.10. entrance of sperm = stimulate secondary oocyte to complete meiosis 2
9.4.11. nucleus of egg develop into female pronucleus = fuse with male pronucleus = form single nucleus = diploid number of chromosomes (zygote) = fertilisation complete
10. Follicular Phase (0-13)
10.1. development of the follicle
10.2. puberty begins = cells forming wall of primary follicle enlarge & divide = create layer of cells around egg
10.3. cell secrete = create fluid filled space around follicular cells = force egg to edge of follicle (secondary follicle)
10.4. fluid cavity continue growing = follicle enlarge = pushes way to ovary surface = mature follicle
11. scientific inquiry
11.1. ask a question
11.1.1. Begins with problem.
11.1.2. Scientists try to find solution for that problem
11.2. Do background research
11.2.1. review of books
11.2.2. scientific journals
11.2.3. Google/Internet
11.3. construct hypothesis
11.3.1. tentative proposal made to explain certain observations
11.3.2. Often make a prediction based on hypothesis (using if-then reasoning)
11.3.3. a statement
11.3.4. short
11.3.5. single idea that can be tested
11.3.6. links 2 variables and states relationship between them
11.4. Test with an experiment
11.4.1. Prediction based on hypothesis
11.4.2. Variable
11.4.2.1. independant variable
11.4.2.1.1. factor that is being investigated
11.4.2.1.2. deliberately changed to determine its effect
11.4.2.2. dependant variable
11.4.2.2.1. observation or results of the changes made by independant variable
11.4.2.3. controlled variable
11.4.2.3.1. factors kept the same for both control and experimental groups
11.4.2.4. uncontrolled variable
11.4.2.4.1. variables that are not kept the same for control and experimental groups
11.4.2.4.2. overlooked or impossible to control
11.4.3. Repitition
11.4.3.1. Doing same experiment many times
11.4.3.2. Performing experiments on larger sample size
11.4.3.3. Test reliability
11.4.4. Placebos
11.4.4.1. inactive substance that looks like real medications
11.4.4.2. In forms of pills, tablets, injections, mock-surgery
11.4.4.3. One group (control group) gets placebos which looks identical
11.4.4.4. if difference between 2 groups clear
11.4.4.4.1. drug is effective
11.5. Analyse results and draw conclusion
11.5.1. data collected in forms of
11.5.1.1. table
11.5.1.1.1. organised
11.5.1.2. graphs
11.5.1.2.1. easy to see trends
11.5.1.3. bar or column graphs/histograms
11.5.1.3.1. when there are many categories
11.5.1.4. quantitative data
11.5.1.4.1. can be measured
11.5.1.4.2. length, height, area, volume, weight
11.5.1.5. qualitative data
11.5.1.5.1. observed, not measured
11.5.1.5.2. colours, textures, smells tastes
11.5.1.5.3. appearance, beauty
11.6. Conclude hypothesis
11.6.1. TRUE
11.6.2. FALSE
11.7. Report results for peer review
12. Cellular Respiration
12.1. energy goes to..
12.1.1. 60%
12.1.1.1. heat to keep body at const. temp. (homeostasis)
12.1.2. 40%
12.1.2.1. used to form ATP (adenosine triphosphate)
12.1.2.1.1. energy required for...
12.1.2.1.2. formation of ATP
12.2. C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + energy
12.3. 20 seperate reactions in series needed (with help of enzymnes) to control release of energy
12.4. 2 types
12.4.1. anerobic
12.4.1.1. occurs in cytoplasm
12.4.1.1.1. enzymes for anaerobic r.
12.4.1.2. breakdown of glucose without oxygen
12.4.1.3. no oxygen available = 2 mol of pyruvic acid = 2 lactic acids
12.4.1.4. during vigorous exercising, oxygen unable to supply enough O2 to energy demands of contractin muscles ,= anaerobic r. supplies extra energy
12.4.1.4.1. result - accumulation of lactic acids in muscles (muscle pain)
12.4.1.5. lactic acid then taken by blood to liver = combine with O2 to form glucose then glycolygen
12.4.2. aerobic
12.4.2.1. occurs in mitochondria
12.4.2.2. inner membrane of mitochondria has enzymes needed for 20 reactions to breakdown glucose in cellular respiration
12.4.2.2.1. inner membrane of mitochondria is folded = karge SA for reaction to take place
12.4.2.3. pyruvic acids = broken down to CO2 and H20
12.4.2.3.1. enzymes in mitochondria = 2 more series of reactions to occur
13. circulatory system
13.1. body's main internal transport system
13.2. link between cells inside body and environment outside body
13.3. blood
13.3.1. transport link between all cells in body
13.3.2. functions
13.3.2.1. transport oxygen and nutrients to cells
13.3.2.2. transport CO2 and other wastes products away from cells
13.3.2.3. maintain PH of body fluids
13.3.2.4. maintain body temp = distribute heat
13.3.2.5. maintain water content, ion concentration of body fluid
13.3.2.6. protect against disease-causing micro-organisms
13.3.2.7. clotting when vessels damaged
13.3.3. consists of
13.3.3.1. 55% plasma (liquid)
13.3.3.1.1. 91% water
13.3.3.1.2. rest made up of dissolved substances (nutrients, ions, gases, hormones, proteins, wastes
13.3.3.2. 45% formed elements (non-liquid), (cell and cell fragments)
13.3.3.2.1. white blood cells (leucocytes)
13.3.3.2.2. red blood cells (erythrocytes)
13.3.3.2.3. platelets (thrombocytes)
13.4. special organs needed to extract requirements from environment
13.4.1. respiratory system
13.4.1.1. absorb oxygen
13.4.2. digestive system
13.4.2.1. absorb protein
13.5. Other organs pass waste from body to environment
13.5.1. respiratory system
13.5.1.1. excretes CO2
13.5.2. digestive system
13.5.2.1. kidneys excrete wastes
14. DNA
14.1. DNA= deoxyribonucleic acid
14.2. molecule strucuture
14.2.1. in form of long strands
14.2.1.1. length 2-3m
14.2.1.2. width 1/2000000th of mm
14.2.2. long mol can fit in small nucleus space
14.2.2.1. DNA strand coiled around histones
14.2.3. if cell not dividing
14.2.3.1. coiled DNA forms tangled network =chromatin
14.2.4. if cell dividing
14.2.4.1. must keep DNA intact during cell division
14.2.4.2. chromatin become chromosomes
14.2.4.2.1. coiled chromatin becomes even more tightly coiled = chromosomes (can be seen with light microscope)
14.3. DNA strucuture
14.3.1. double helix
14.3.2. nucelotide
14.3.2.1. each phosphate group and sugar molecule with a nitrogen base
14.3.2.2. units making up DNA molecule
14.3.3. 4 nitrogen bases
14.3.3.1. adenosine - thymine
14.3.3.2. cytosine - guanine
14.3.3.3. weak hydrogen bond between base pairs
14.3.4. view diagram
14.4. Replication of DNA
14.4.1. undergoing process between cell division.
14.4.2. results in formation fo new DNA mol tht are identical = form exact replicas of themselves
14.4.3. process
14.4.3.1. 2 linked chains of DNA mol seperate
14.4.3.2. easy = weak hydrogen bond between bases
14.4.3.3. each seperated section = contain half original info= serve as templates for nucleotides tht will form other new half ( A-T, C-G)
14.5. Role of DNA
14.6. nuclei of human cell
14.6.1. 46 DNA mol
14.6.2. DNA mol contain genes
14.6.2.1. section of mol
14.6.2.2. contain genetic code
14.6.2.3. determine structure & activities of cell
15. Digestive System
15.1. extracts nutrients from food we eat and absorbs them into body for use by cells
15.2. Digestion is process in which carbohydrate, protein and fat mol broken down to products small enough to be absorbed by cells.
15.3. Organs specially structured and arranged = carry out 6 activities
15.3.1. ingestion of food and water
15.3.2. mechanical digestion of food
15.3.3. chemical digestion of food
15.3.4. movement of food along alimentary canal
15.3.5. absorption of digested food and water into blood and lymph
15.3.6. elimination of material that is not absorbed
15.4. Alimentary canal = continuous tube tht runs from mouth to anus
15.5. Study worksheet
15.6. Diagram of villi
15.7. Diet
15.7.1. Affects absorption in alimentary canal
15.7.2. speed of material moving through alimentary canal
15.7.2.1. Size and contents of meal
15.7.3. Material pushed into small intestines more quickly
15.7.3.1. large meal (causes greater stretching of stomach)
15.7.4. Process is slow of movement from stomach to small intestine
15.7.4.1. Consume high protein, high fat content
15.7.5. Alcohol/ caffeine stimulate movements in stomach
15.8. Illnesses
15.8.1. Constipation
15.8.1.1. movements of large intestines reduced, contents remain there too long
15.8.1.2. water is absorbed = faeces become drier, harder than usual
15.8.1.3. Defecation becomes difficult/ painful
15.8.1.4. Due to lack of roughage in diet (cellulose/ insoluble fibre. lack of exercise, emotional problems
15.8.1.4.1. Roughage stimulates movement of alimentary canals
15.8.2. Diarrhoea
15.8.2.1. frequent defecations of watery faeces
15.8.2.2. Due to irritation of small/large intestines = (caused by bacterial or viral infection)
15.8.2.3. Increases peristalsis = contents move through intestines too fast = not enough water absorption
15.8.3. Bowel Cancer
15.8.3.1. uncontrolled growth of cells of walls of large intestines
15.8.3.2. unbalanced diet (high consumption of red and processed meat and low consumption offibre
15.8.3.3. high alcohol consumption/ smoking
15.8.3.4. Overweight, obese, physical inactivity
15.8.4. Coeliac disease
15.8.4.1. cannot tolerate gluten
15.8.4.2. gluten = wheat, rye, barley
15.8.4.3. if eaten= immune system responds = damaging / destroying villi in small intestines
15.8.4.4. Therefore, nutrients can't be absorbed
15.8.4.5. Inherited, symptoms : muscle cramps, joint pain, leg tingling
15.8.5. Importance soluble fibre
15.8.5.1. Sources : fruits, vegetables, soy, barley products
15.8.5.2. Links to low cholesterol in blood
15.8.5.3. decrease = risk of heart diseases, cancer
15.8.5.4. benefit effect on glucose levels
15.8.5.5. fats in intestines trapped by soluble fibre = prevent their absorption by the body
16. Production of sex cells
16.1. production of sperm/egg
16.1.1. reproductive systems specialise for production of male/female sex cells (gametes)
16.1.2. gametogenesis
16.1.2.1. meiosis results in half chromosome-new cells, developing into gametes (sperm or egg)
16.1.2.2. 2 types
16.1.2.2.1. spermatogenesis
16.1.2.2.2. oogensis
16.1.3. male (spermatozoon) & female (ovum) gametes fuse together at fertilisation = form zygote
16.1.3.1. gametes = have only half the chromosome number of body cells (meiosis)
16.1.4. from zygote = multicelled organism develop