UNICELLULAR ORGANISM

                                                                                                                                        Any organism which consits of one cell is a...

       UNICELLULAR ORGANISM 

The structure of bacteria...

Each of the cell components has a specific function...

THE CELL

PLANT AND ANIMAL CELLS

The cell is the fundemental unit of all living organisms. Many plant and animal cells have certain parts or components in common. Some of these parts are found in both animal and plant cells, while others are only in plants.

CELL COMPONENTS

Each component of a plant or animal cell has a specific function.

SEEING CELLS

Almost all cells are too small to be seen using your eyes. They are microscopic and so require microscopes to see them. Microscopes were invented by a scientist called Robert Hooke in the 17th century. Scientists could now see single-celled organism for the first time.

MAJOR GROUPS OF ORGANISMS

•Biologists classify organisms, putting them into groups.

•Each group reflects similarities of structure and function that have come about because the organisms in the groups.

•Each group reflects similarities of structure and function that have come about because the organisms in the groups are related through their common ancestry.

•In other words, they are descended from the same ancestors by the process of evolution.

1. Plants

•Plants are multi-cellular organisms

•They vary greatly in size from over 100 metres to 50mm

•They contain chloroplasts for photosynthesis

•All plant cells have a cell wall made of a sugar carbohydrate called cellulose

•Plants can make a variety of other carbohydrates from the process photosynthesis, these include starch which is used as an energy store and also sucrose (table sugar)

Examples: Pea Plant, Maize Plant, Oak Tree, Venus Fly Trap

2. Animals

•Animals are multi-cellular organisms

•They vary greatly in size from over 30 metres to smaller than 1mm

•They DO NOT contain chloroplasts

•Animal cells DO NOT have a cell wall

•Most animals store their energy in the form of the carbohydrate glycogen

•Not all bacteria are bad- some can do good and useful things inside out bodies

Examples: House fly, Jelly Fish, Lion

3. Fungi

•Some fungi can be seen with the naked eye and are multi-cellular including mushrooms and some are made from single cells, like yeast

•Fungi can have lots of different shapes

•Fungus cells are a similar to plant cells in that they have a cell wall BUT it is made from chitin

•They differ to plant cells as they DO NOT contain chloroplasts

•Some fungi send out threads which grow into the body of a dead organism known as hyphae

•They respire, releasing carbon dioxide

•They reproduce by releasing spores or by budding (in yeast)

•Some fungi are useful

•You can get rid of a fungal infection with a fungicide

Examples: Athletes foot, mould that produces penicillin, yeast

4. Protosists

•The Protista, or Protosista, are a kingdom of simple organisms, usually composed of a single cell or a colony of similar cells. Protists live in water, in moist terrestrial (land) habitats, and as parasites and in the bodies of multicellular eukaryotes (organisms which cells contain a true nucleus).

•Protists are single-celled and usually move by cilia (hair like projections) or by flagella (tail-like projections). There is usually no cell wall, although some forms may have a cell wall. They have organelles (components of a cell) including a nucleus and may have chloroplasts, so some will be green and others won't be. They are small, although many are big enough to be recognized by a microscope or even with a magnifying glass. Protists get their nutrition by photosynthesis, ingestion of other organisms, or both.

5. Bacteria

•Bacteria are single celled organisms

•They can be a range of different shapes and sizes, usually about 0.001mm or 1mm

•All bacteria have a cell wall

•All bacteria have free, circular DNA that is not in a nucleus

•Bacteria can divide just like other cells

•They divide most rapidly if the conditions are just right for that particular bacteria

•You can get rid of a bacterial infection with antibiotics

•Not all bacteria are bad- some can do good and useful things inside out bodies

Examples: Salmonella (food poisoning), streptococcus (sore throat), lactobacillus (used to make yoghurt)

6. Viruses

•Viruses are very small (about 0.01 mm)

•They are made of DNA and protein

•They are not cells- they don’t have a nucleus and can’t reproduce on their own

•To reproduce, they have to enter a living cell and can only succeed by relying on other living cells (they are parasites). The cell is given instructions by the viral DNA to produce lots more of the virus

•Viruses can lay dormant for years before they become active in a living cell

•Viruses can be transmitted through air, blood, faeces…pretty much any way. They just need a live cell to start dividing when they reach their destination.

•They can be fought off by the immune system in the body and vaccines, but antibiotics have no effect on them

Examples: cold virus, influenza, measles, tobacco mosaic virus (effects the tobacco plant)

LIFE PROCESSES

MRS GREN 

Living things have certain life processes in common. There are seven things that they need to do to count as being alive. The phrase MRS GREN is a way to remember them: 

Movement

Respiration 

Sensitivity 

Growth 

Reproduction 

Excreation

Nutrition

All living organisms on Earth are divided in pieces called cells. They are small compartments that hold all of the biological equipment necessary to keep an organism alive and successful on Earth. 

Cell Metabolism

A cell's daily operations are accomplished through the biochemical reactions that take place within the cell. Reactions are turned on and off or sped up and slowed down according to the cell's immediate needs and overall functions. At any given time, the numerous pathways involved in building up and breaking down cellular components must be monitored and balanced in a coordinated fashion. To achieve this goal, cells organize reactions into various enzyme-powered pathways.

Factors affecting the rate of enzyme activity

The rate of enzyme activity increases with as temperature increases until the best temperature, then falls to zero as the enzyme is denatured. This means that the protein changes shape and the active site is no longer complementary to the substrate molecule.
How the cell gets its energy

In fact, the Sun is the ultimate source of energy for almost all cells, because photosynthetic prokaryotes, algae, and plant cells harness solar energy and use it to make the complex organic food molecules that other cells rely on for the energy required to sustain growth, metabolism and reproduction. Cellular nutrients come in many forms, including sugars and fats. 

Cellular respiration 

Cellular respiration is the process by which the chemical energy of "food" molecules is released and partially captured in the form of ATP. Carbohydrates, fats, and proteins can all be used as fuels in cellular respiration, but glucose is most commonly used as an example to examine the reactions and pathways involved.
Respiration is a series of reactions in which energy is released from glucose. Aerobic respiration is the form of respiration which uses oxygen. It can be summarized by this equation:
glucose + oxygen → carbon dioxide + water (+ energy) Energy is shown in brackets because it is not a substance. Notice that: Glucose and oxygen are used up Carbon dioxide and water are produced as waste products.

Aerobic respiration 

Aerobic respiration happens all the time in the cells of animals and plants. Most of the reactions involved happen inside mitochondria, tiny objects inside the cytoplasm of the cell. The reactions are controlled by enzymes.
Anaerobic respiration 

Not enough oxygen may reach the muscles during exercise. When this 

happens, they use anaerobic respiration to obtain energy.Anaerobic respiration involves the incomplete breakdown of glucose. It releases around 5% of the energy released by aerobic respiration, per molecule of glucose. The waste product is lactic acid rather than carbon dioxide and water:glucose → lactic acid (+ little energy) 

Oxygen debt 

Aerobic respiration provides enough energy to keep the over worked muscles going for a short period, but continuing the “burst” activity makes lactic acid build up in the blood stream, producing muscle cramps the person then has to rest to oxidise the lactic acid fully. This uses oxygen. The volume of oxygen needed to completely oxidise the lactic acid that builds up in the body during anaerobic respiration is called the oxygen debt.

Cells, tissues, organs and organ systems

Pls. remember that the below process doesn't only occur to the circulatory system but to other organ systems too.

WELCOME

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