Biology Notes

Variety of Living Organisms Plants: Multicultural organisms Contain chloroplasts and are able to carry out photosynthesis Have cellulose alls outside the cell walls to provide support to the cell Store carbohydrates as starch and sucrose Have large permanent vacuoles filled with cell sap that contains water and dissolved substances Vary greatly in size and shape CLC Example of flowering plant: Rose C] Examples of cereals: Maize CLC Examples Of non-flowering plant: Conifers Animals: o Multicultural organisms o Do not contain chloroplasts and cannot carry out photosynthesis o Do not have cell walls o Have small temporary vacuoles o Usually have a nervous system and can move from one place to another o Often store carbohydrates as glycogen C] Example of a vertebrate is human 0 Example of invertebrate is earthworm Fungi: o Cannot carry out photosynthesis o Some are multicultural: C] Consist of McCollum made from thread-like structures called hyphen, which contain many nuclei C] Reproduce by spores Example: Mucous 0 Some are single celled: Page 1 of 46 Grade 10 Biology Revision Guide Have cell walls made of chitin Reproduce by budding Yeast o Feed by extracurricular secretion of digestive enzymes onto the food material and absorption of the organic products.

Also known as saprophytic nutrition. O Store carbohydrates as glycogen. Bacteria: o Microscopic single-celled organisms. O Lacks a nucleus but contains a circular chromosome of DNA o They have cell walls, cell membrane, cytoplasm and plasmids o Some can produce their own food during photosynthesis as they have chlorophyll o Some feed off other living or dead organisms and are known as decomposer o Many can move around using one or more flagella and have a protective layer around the cell wall called a capsule CLC Example: Lascivious Bulgarians, a rod shaped bacterium is used in the production of yoghurt from milk Pneumatics, a spherical bacterium causes pneumonia

Protracts: o Microscopic single celled organisms o They have a true nucleus and other organelles o Some are animal like while others resemble plant or fungus cell structure o All have a simple cell structure C] Example: Amoeba have features like animal cell and they live in pond water Chloral have chloroplasts and are more like plants Plasmids is a pathogen that causes malaria Virus: o Small particles – smaller than bacteria o Are parasite as they can only reproduce inside living cells o Infect every type of living organism o Have a wide variety of shapes and sizes Have no cell structure but have a protein coat called sapid and a core that contains one type Of nucleic acid , either DNA or RNA L] Example: Tobacco mosaic virus that causes the discoloring of the leaves of tobacco plants by preventing the formation of chloroplasts Influenza virus that causes flu in humans. Influenza spreads by droplet infection HIVE that cause AIDS. AIDS spreads by exchange of body fluids HI IN virus that causes swine flu. Swine flu spreads by droplet infection Page 2 of 46 pathogen: Any organism or agent, capable Of causing disease or infection. This may be in the form of virus, bacteria, protracts or fungi.

BACTERIA CELL VIRUS CELL Page 3 of 46 PLANT CELL ANIMAL CELL FUNGI CELL page 4 of 46 Cell Structure and Organization PLANTS ANIMALS Cell Membrane Cytoplasm Nucleus Cell wall made up of cellulose No cell wall Chloroplasts contains chlorophyll No chloroplasts Large permanent vacuoles containing cell sap Small temporary vacuoles Store carbohydrates in the form of starch Store carbohydrates in the form of glycogen Cell wall: Protects supports and gives a fixed shape to plant cells; totally permeable. Cell Membrane: Controls the substances that enter and exit the cell; selectively permeable. Cytoplasm: Jelly like fluid containing cell organelles; living material in which chemical reactions take place.

Nucleus: Controls all activities in the cell since it contains the genetic information. Chloroplast: Contains chlorophyll that absorbs light for photosynthesis. Vacuole: Stores cell sap – solution of water, dissolved sugars, mineral ions and other solutes. Organelles cells Tissues Organs Organ Systems Organisms Organelles group together to form cells. O For example, cell membrane, nucleus and cytoplasm forms a cell. Cells are grouped together to form tissues. 0 For example, red blood cells and white blood cells form blood tissue. Tissues are grouped together to form organs. O For example, blood tissue, nerve tissue and muscle tissue forms the stomach.

Page 5 of 46 Organs work together to for organ systems. O For example, stomach, intestine, liver and pancreas work together to form the digestive system. Several organ systems make an organism. O The digestive system, nervous system, circulatory system, respiratory system, excretory system and reproductive system form an organism. Biological Molecules Carbohydrates: o Carbon, Hydrogen and Oxygen Lipids: C] Same as carbohydrates, however, it has a higher proportion of hydrogen and a lower proportion of oxygen Proteins: o Carbon, Hydrogen, Oxygen and Nitrogen CARBOHYDRATES Inconsistencies: Disaccharide: Polysaccharides: Simple sugars like glucose.

Double sugars formed from two inconsistencies – like maltose. Large molecules formed from many inconsistencies – starch and glycogen. Glucose: Is a macroeconomics Is the major energy source for most cells It is highly soluble and is the main form in which carbohydrates are reinserted around the body of animals Is a hexes sugar meaning it is hexagonal in structure C6H1206 Page 6 of 46 An example is starch as it is made up of many molecules of glucose and is the major carbohydrate storage molecule in plants. Are mainly used as an energy store and structural components in cells. Main ones include starch and cellulose in plants, and glycogen in animals.

PROTEINS Groups of large and complex molecules made up of long chains of amino acids. O Amino acids are the building blocks of proteins. Are the main components of body tissues, such as muscle, skin, ligaments ND hair. O All enzymes are proteins, cataloging many biochemical reactions. O Many hormones are proteins LIPIDS Are made up of fatty acids and glycerol. O Important lipids include waxes, steroids and cholesterol. Provides more than twice the amount of energy as carbohydrates. Needed for heat insulation: o In mammals, fat deposits underneath the skin to help reduce heat loss. Needed for protection: o Fatty tissue around delicate organs such as kidneys acts as a cushion against impacts.

TEST FOR STARCH PROCEDURE Take a small piece of a food sample and place it on a white tile. Add 2-3 drops of Iodine solution. Page 7 of 46 OBSERVATION If sample turns blue-black in color, starch is present. If sample remains brown in color, starch is absent. TEST FOR GLUCOSE Take a small piece of a food sample and put it in a test tube. Add some water and shake to dissolve the glucose (if any). Add some Benedicts solution. Heat the test tube in a hot water bath. If sample changes from blue to green to yellow to brick red, glucose is present. If sample remains blue in color, glucose is absent. If sample turn into a greenish color, there is a low concentration of glucose.

Remember to wear safety goggles during the experiment and to us a holder to hold then test tube in such a way that the mouth of the test tube faces away from you as the solution squirts while boiling. ENZYMES Are biological catalysts: o Catalysts are substances that increase the rate of chemical reactions without being used up. O Without catalysts, most of the reactions that happen in cells WOUld be far too slow to allow life to go on. Are proteins that are folded into complex shapes that allow smaller molecules to fit into them. The place where a substrate molecule fits is the active site. Are needed to lower the energy required for the reactions and speed them up to produce the end product quickly. Are produced by cells: o Cells contain hundreds of different enzymes, each cataloging a different reaction.

Enzymes are inactivated by poisons as the poison fits into the active site blocking it temporarily or permanently. Page 8 of 46 LOCK AND KEY HYPOTHESIS FACTORS AFFECTING ENZYMES: Temperature pH Concentration of substrate Concentration of enzyme The optimum: o The optimum temperature is the temperature at which the activity of an enzyme is greatest. The optimum pH value is the pH value at which the activity of an enzyme is greatest. However, different enzymes have different optimums. The enzyme is denatured when: o The shape of an enzyme changes, as its active site may no longer work. њ This usually happens at high temperatures or at extremes of PH.

TEMPERATURE At high temperature, there is lots of kinetic energy increasing the number of collisions which means that substrates combine with the active site quickly increasing the rate of reaction. Very high temperatures denature enzymes. When the enzymes are denatured, the rate of reaction decreases. At low temperatures, there is little kinetic energy and hence fewer collisions which means that substrates combine with the active site slowly reducing the rate of reaction. PH Changes in pH alter an enzymes shape. Different enzymes work best at different pH values. The optimum pH for an enzyme depends on where it normally works. O For example, intestinal enzymes have an optimum pH of about 7. 0 However, enzymes in the stomach have an optimum pH of about 2 Page 9 of 46 Enzymes are specific which mean that they only work on one type of substrate.