These Slides contain EVERYTHING in Biology A Concise Revision Course for CXC.
The notes provide should be able to help anyone understand Biology with or without some sort of previous knowledge.
Topics covered:
Living Organisms
The Cell
The Chemistry of Life
Nutrition
Transport Systems
Food Storage
Respiration and Gaseous Exchange
Excretion and Osmoregulation
Movement and Support
Sensitivity and Co- Ordination
Growth and Development
Reproduction
Homeostasis
Disease and Man
Continuity and Variation
Life and the Enironment
Slide 2
1. Living Organisms
Living Organisms can be classified in to small groups based on their observable appearance.
Classification divides the organisms from large groups called Kingdoms which then break down into Phyla, then to Classes, then Order, then Families, then Genre, then Species.
Kingdoms:
Viruses:
Tiny particles made up of nuclear materials(DNA) enclosed in a protein coat.
Bacteria:
Unicellular Organisms
Lacks a true nucleus, DNA is spread throughout the cell
Fungi:
Body consists of a network of thread like hyphae which make up mycelium.
Reproduce by spores
Protoctists:
Has a true nucleus.
Unicellular
No Cell Wall present
Plants:
Usually Stationary
Cells have cell wall and contain chlorophyll
Makes their own food via photosynthesis
Animals:
Usually move around
Feed on other organisms
Cells lack cell wall and chlorophyll
Slide 3
1. Living Organsisms cont'd
Characteristics of Living Organisms:
G - Growth - This is the permanent increase in the dry mass of an organism.
R - Respiration - This is the release of energy from food.
I - Irritability - This is the ability of an organisms to detect and respond to spontaneous stimuli.
M - Movement - This is the change in position of part of, or the whole organism.
N - Nutrition - This is the intake of food by an organism for growth and repairs to the body.
E - Excretion - This is the removal of metabolic waste from the organism.
R - Reproduction - This can be done Sexually or A- Sexually. Sexually requires a male and female of the species, the offspring is genetically different from the parent. A-Sexually only requires one parent of the species, and the offspring is genetically the same as the parent.
Slide 4
2. The Cell
The cell is the simplest unit of life.
The Animal cell contains:
Cell Membrane - semi-permeable, controls what enters and leaves the cell.
Cytoplasm - Supports organelles
Glycogen Granules - food stores
Mitochondrion - site of respiration
Centrioles - Forms spindle in cell division
Nuclear Membrane, Nucleoplasm, Chromatin Threads, Nucleolus (Nucleus) - essential for cell division, contains cell information.
Vacuole - contains water, food or cell secretions
The Plant Cells contains:
Cell Wall - Freely permeable, supports the cell
Cell Membrane
Cytoplasm
Mitochondrion
Chloroplast - Contains chlorophyll and is the sit of photosynthesis
Starch Grains - Food stores
Large Central Vacuole - Contains cell sap, supports cell when turgid and stores waste.
Nucleus
Differences of Animal Cell to Plant Cell
Usually circular in shape
No cell wall
No chloroplast or chlorophyll
Has several small vacuoles
Has Glycogen Granules as food stores
Differences of Plant Cell to Animal Cell
Usually rectangular in shape
Has a cell wall
Has chloroplast and chlorophyll
Has one large central vacuole
Has Starch Grains for food stores
Slide 7
2. The Cell cont'd
Cell Specialization is differentiation of cells to carry out specific Jobs.
Unicellular organisms are unspecialized, so the cell is capable of carrying out all life processes.
Multicellular organisms consists of several groups of cells, where each group carries out a specific task. They begin with organelles which work together to form cells. The cells then work in groups to form tissues. Tissues group together to form organs. Organs work together in systems and Systems work together to form multicellular organisms.
Slide 8
3. The Chemistry of Life
The Human body consists mainly of Water, Protein, Lipids, Carbohydrates, Inorganic Substances and other Organic substances.
Carbohydrates :
Carbohydrates exist as three(3) groups,
Monosaccharides - or single sugars are sweet and soluble. Example: Glucose, Fructose and Galactose.
Disaccharides - or double sugars are sweet and soluble. Example: Maltose (Glucose + Glucose) Sucrose (Glucose + Fructose) or Lactose (Glucose + Galactose).
Polysaccharides - or multi-sugars are not sweet and are insoluble. Examples: Starch, Cellulose and Glycogen.
Lipids (fats and oils) :
Lipids have less oxygen than carbohydrates. They are made up of 3 fatty acid molecules, and 1 glycerol molecule.
Proteins :
Proteins are made up of Amino acids which are joined together by peptide links to form chains called Polypeptides.
Slide 9
3. The Chemistry of Life
Enzymes are biological catalysts. They speed up chemical reactions without being altered or denatured.
Properties of Enzymes:
Enzymes are Proteins which are obtained from amino acids in diets of animals and manufactured by plants.
Enzymes are Specific meaning they control only one type of reaction, to produce the same products.
Enzymes can be reused due to their inability to be destroyed or altered in reactions.
Enzymes are only required in small amounts as they are reusable.
Enzymes work best at Optimum Temperature (37 degrees Celsius for Humans)
Enzymes are denatured at high temperatures.
Enzymes work best at Optimum pH (7)
Enzymes are denatured by extreme Acidity or Alkalinity.
Enzymes are boosted by Vitamins and Minerals.
Enzymes are inhibited () by poisons
Slide 10
4. Nutrition
There are 2 Types of Nutrition:
1) Autotrophic Nutrition
Organisms (Mainly green plants) manufacture organic food from inorganic substances such as Carbon Dioxide, Water and a form of Energy.
Photosynthesis - Green plants use energy trapped from the sun
Chemosynthesis - Some bacteria use energy from the breakdown of other inorganic compounds such as ammonia, hydrogen or sulphide.
2) Heterotrophic Nutrition
Organisms obtain ready made organic food from the environment.
Holozoic Nutrition - solid organic food is obtained from consuming other organisms.
Saprophytic Nutrition - soluble organic food is obtained from dead or decaying matter.
Parasitic Nutrition -