Characteristics of Living Beings:
Characteristics that all things have in common at some point in their life:
1. Movement: Locomotion of at least part of an organism’s body.
2. Nutrition: Required by organisms to provide energy, enable growth, maintain and reproduce themselves. Can be either heterotrophic or autotrophic.
3. Growth: The development of an organism to increase size, by in-taking food substances different than themselves and changing it chemically to allow their cells to increase in size and number.
4. Respiration: Energy is obtained from food in a chemical reaction which usually requires oxygen and produces carbon dioxide, water and energy. This process is called respiration.
5. Reproduction: Production of new individuals from existing ones.
6. Excretions: Removal of waste products of metabolism from the body.
7. Response: An organism’s ability to respond to changes in both the internal and external environment.
Heterotrophic:
When an organism survives on the intake of organic matter derived from other living organisms. It is therefore dependant on other organisms.
Autotrophic:
The ability of an organism to derive nutrition through either photosynthesis or chemosynthesis. It is therefore able to produce its own food.
Photosynthetic:
An organism’s ability to use the process of photosynthesis to produce its own food.
Chemosynthetic:
The ability to use chemical reactions to produce their own food, like anaerobic bacteria.
Asexual:
Reproduction requiring only one parent – offspring are genetically identical to their parent.
Sexual:
Reproduction requiring both a male and female parent.
Death:
When an organisms life processes stop.
Metabolism:
The ongoing interrelated series of chemical reactions taking place in a living organism that provide the energy and nutrients required to sustain life.
Classification:
The grouping together of organisms which demonstrate similar structures – this is called natural classification. It is based on relatedness and shows genetic as well as revolutionary relationships.
Hierarchical System of Classification:
Classification is based on a system of hierarchy. As we move down each level the similarities become greater and the differences fewer. These levels or the hierarchy are:
1. Kingdom;
2. Phylum;
3. Class;
4. Order;
5. Family;
6. Genus;
7. Species.
Taxon:
The groups to which organisms are assigned to.
Dichotomous Key: A key where different organisms are separated.
Substrate:
Molecules that react.
Organelle:
Membrane-bound subdivision of the cell, specialised for a specific function.
Symbiotic Relationship:
The relationship between two organisms where they cannot be separated from the other and survive.
Epiphytic:
A plant that grows on top of another or is supported by another plant but does not depend on it for nutrition.
Enzymes:
Protein produced by living cells that promotes a specific biochemical reaction by acting as a catalyst.
Catalyst:
A substance that increases the rate of a chemical reaction without itself undergoing any change.
Genes:
The basic unit capable of transmitting characteristics from one generation to the next. It consists of a specific sequence of DNA or RNA that occupies a fixed position (locus) on a chromosome.
Chromosome:
Rod-shaped structure in a cell nucleus carrying the genes that determine sex and the characteristics an organism inherits from its parents.
Gamete:
Reproductive cell which is either male or female with half the normal number of chromosomes that unites with another cell of the opposite sex.
Cotyledons:
The leaf or leaves produced by the seed of a flowering plant.
Prokaryote Cells:
Are small and do not have a membrane bound nucleus. Bacteria, cyanobacteria and blue-green algae are made up of these cells. Prokaryotic organisms perform specialised tasks but without organelles. Instead chemical reactions are used within the various regions of the cell.
Eukaryote Cells:
Contains a membrane bound nucleus. Plants, animals, fungi and protists are made up of these cells. Eukaryotic organisms possess membrane bound organelles which preform specialised tasks – eg. The mitochondria carry out respiration.
Kingdom Monera:
Bacteria:
1. Are unicellular;
2. Made up of prokaryotic cells;
3. Contain RNA and DNA;
4. Divide by binary fission
5. Most are surrounded by a rigid cell wall;
6. May be motile using flagella;
7. Some form bacill; (Spores which are very difficult to kill)
8. Three main shapes: Spherical (Cocci)
: Coiled (Spirilla)
: Rod shaped (Bacilli)
9. Are classified using: size, shape, colour, reaction to stains and reactions to various conditions.
10. To survive bacteria generally require moist conditions to grow and reproduce. However different species have different temperature optimums and preferences.
11. Aerobic bacteria require oxygen for respiration while others are anaerobic and do not require oxygen to survive.
12. They can be autotrophic, chemosynthetic or heterotrophic.
13. Eventually all naturally occurring substances can be broken down by bacteria.
Kingdom Protista:
1. Contains algae, protozoans, water moulds and slime moulds.
2. Most are single celled, but some are multicellular like brown kelp which can grow to be 60 metres long.
3. Although some may be plant-like, fungi-like or animal-like they lack the specialised features of these groups.
4. Occur in aquatic or at least moist environments.
5. May be free-living but some are parasite which cause disease.
Algae Classification:
Algae are classified according to their colour:
1. Dinoflagelletes and golden algae are microscopic plankton that are yellow-brown in colour.
2. Rhodophyta: Red algae
3. Phaeophyta: Brown algae
4. Chloraphyta: Green algae
Kingdom Fungi:
1. Secrete enzymes over the surface of their food and absorbs the broken down products directly.
2. Non-motile like plants.
3. Do not photosynthesise.
Made up of tiny threads called mycelium and reproduce by spores. Examples include bread mould, yeast, mushrooms, smuts and rust.
Lichens:
Are the result of a symbiotic relationship between algae and fungi.
Kingdom Plantae:
Plants are classified on the basis of constituent characteristics: such as structure. They are divided into two main groups:
1. Bryophytes: Which lack conducting tissue (veins) such as mosses and liverwort.
2. Tracheophytes: Are the largest group and contains all the “modern” plants such as grasses and trees.
Phyllum Bryophytes:
1. Are simple plants;
2. Lack tree roots;
3. Lack true stems and leaves;
4. No vascular tubes;
5. Small and clumping;
6. Require moist environments;
7. Have a reproductive cycle which contains both an asexual (spore) and sexual stage.
Phyllum Tracheophytes:
Can be divided into a variety of groups based on their structural characteristics. Most vascular plants have a well developed shoot and root system.
Phylum Pteridophyta (Filicopsida):
1. The group of ferns;
2. Reproduces through spores;
3. Usually ground plants but may be epiphytic; (tree-like)
4. Live in most environments; (free swimming sperm)
5. Have alternation of generation. (a two part lifecycle)
Phylum Coniferopsida:
1. Conifers: Pines, cypresses, cedars and redwoods and are found mainly in the northern hemisphere;
2. Mostly large, woody land plants;
3. Usually scale-like needle leaves;
4. Gametes produced in separate cones;
5. Naked seeds develop in cones. (not enclosed in fruit)
Phylum Ginkopsida:
1. Ginkgo or maiden-hair tree;
2. Large woody tree;
3. Fan-shaped deciduous (sheds in autumn) leaves with veins branching in twos;
4. Distinct male and female plants;
5. Seeds naked on scales.
Phylum Cycadopsida:
1. Cycads;
2. Palm-like plants;
3. Leaves are large and subdivided in a pinnate way; (resembling a feather)
4. Gametes produced in cones on different plants;
5. Cones are massive and fleshy;
6. Seeds naked on scales of cone.
Phylum Angiospermae:
1. Flowering plants, grasses, herbs, shrubs and trees;
2. All produce flowers;
3. Produce seeds inside a specialised fruit;
4. Divides into two subclasses: Monocotyledonae (one seed leaf) and dicotyledonae (two seed leaf).
Class Monocotyledonae:
1. Stem anatomy: Vascular bundles are scattered
2. Seed morphology: Embryo has one cotyledon (seed leaf).
Class Dicotyledonae:
1. Stem anatomy: Rings of vascular bundles
2. Seed morphology: Embryo has two cotyledons (seed leaves).
Kingdom Animalia:
1. Phyllum Porifera – Sponges
2. Phyllum Coelenterata (cnidaria) - Jelly fish, corals
3. Phyllum Platyhelminthes (flatworms) – Planaria, liver flukes, tape worms
4. Phyllum Nematodes (roundworms) – Ascaris, thread worms.
5. Phyllum Molluscs: Gastropoda – Snails, slugs
: Bivaloia – Oysters, clams
: Cephlapoda – Squid
6. Phyllum Annelida – Worms
7. Phyllum Arthropoda – insects, spiders, centipedes, crabs
8. Phyllum Echinodermiata – starfish, sea urchins
9. Phyllum Chordata: Fish, amphibians, reptiles, birds, mammals
Vacuole:
Cellular inclusion which is small in animals (used for food storage and digestion) and big in plants (used for storage and osmotic control).
Centrioles:
Paired tubular structure found in animals and algae which is involved in cell division.
Turgorpressure:
Water in cell allows it to maintain its shape. Plant with low turgorpressure = wilts.
Plant & Animal Cells:
Plant Cells | Animal Cells |
Cell Wall: Mixture of carbohydrates including cellulose | No Cell Wall but may have carbohydrate coat |
One large vacuole - up to 90% cell volume | Vacuole absent or small |
Chloroplasts in photosynthetic cells | No chloroplasts |
Centrioles absent | Centrioles (involved in spindle formation) present |
Cell Parts:
1. Nucleus: Controls metabolic (cellular function)
2. Cell Membrane: Support and define cell, gives shape and controls movement into and out of the cell.
3. Cell Wall: Found mainly in plants; (but also in bacteria) support cell by turgorpressure.
4. Cytoplasm: Jelly that supports the organelles.
5. Mitochondria: Power house of the cell where respiration occurs (burning up of glucose and fat to create energy).
6. Endoplasmic reticulum: Tubes that connect nucleus to the outside world so it can adjust to changes.
7. Chloroplasts: Site of photosynthesis using chlorophyll – green pigment.
8. Ribosome: Site of proteinsynthesis.
Isotonic:
Having the same concentration as the surroundings.
Movement of cellular substances:
Is dependant upon 3 biological principles.
Diffusion:
Occurs naturally and is the movement of molecules amongst themselves. This is the result of molecular collision which results in the gradual spreading out of molecules until there is an even distribution. This is called the diffusion gradient.
The rate of diffusion is affected by the objects concentration, the temperature and the pressure.
Osmosis:
Occurs with a selectively permeable membrane where the smaller molecules move by diffusion through the membrane. Since larger molecules cannot defuse a concentration difference is created. The diffusion of water through a selectively permeable membrane. This transports the water from an area of high concentration to an area of low concentration.
When the cell membrane extracts molecules against the concentration gradient = energy is expended.
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