1. Characteristics of living organisms

Characteristics of living organisms

Movement, respiration, sensitivity, growth, reproduction, excretion, nutrition, respond to surroundings

Viruses are … organisms.

Non-Living

Describe nutrition in plants:

• Plants use sunlight, carbon dioxide and water to produce oxygen and glucose in the process of photosynthesis

• Because plants create their own food for energy, they are described as being autotrophic

Describe Nutrition in animals:

• Animals consume other living organisms in order to obtain the energy they require

• They break down larger complex molecules into simpler molecules through the process of digestion

• As animals obtain their food from a range of different sources, they are described as being heterotrophic

Respiration:

a chemical reaction carried out in all living organisms, where energy is released from

Excretion:

the removal of metabollic waste

locomotion:

The movement of an organism from place to place

Growth:

a permanent increase in size

What are the 5 living organisms:

• Animals

• Plants

• Fungi

• Protoctists

• Prokaryotes

Nucleus:

Contains the genetic material (DNA) which controls the activities of the cell

Cytoplam:

a gel like substance which provides the cell structure and where chemical reactions and anareobic respiration takes place.

Cell memebrane:

hold the cell together, and controls which substance can enter and leave the cell

Ribosomes:

found in the cytoplams and is site of protein synthesis

Mitochondria:

site of aerobic respiration - powerhouse of a cell

Cell wall:

made of cellulose ( a polymer of glucose) and gives the cell extra support)

Chloroplasts:

contains greenchlorophyll pigments and enzymes for photosynthesis

Permanent vacuole:

contains sell sap, a solution used for the storage of materials and to support the shape of the cell

Describe the common features shown by eukaryotic organisms: plants

• These are multicellular organisms;

• their cells contain chloroplasts and are able to carry out photosynthesis;

• their cells have cellulose cell walls;

• they store carbohydrates as starch or sucrose.

• Examples include flowering plants, such as a cereal (for example, maize), and a herbaceous legume (for example, peas or beans).

Describe the common features shown by eukaryotic organisms: animals

• These are multicellular organisms;

• their cells do not contain chloroplasts and are not able to carry out photosynthesis;

• they have no cell walls;

• they usually have nervous co-ordination and are able to move from one place to another;

• they often store carbohydrate as glycogen.

• Examples include mammals (for example, humans) and insects (for example, housefly and mosquito).

Describe the common features shown by eukaryotic organisms: fungi

• These are organisms that are not able to carry out photosynthesis;

• Multi-cellular fungi are usually organised into a mycelium made from thread-like structures called hyphae, which contain many nuclei;

• their cells have walls made of chitin; they feed by extracellular secretion of digestive enzymes onto food material and absorption of the organic products;

• this is known as saprotrophic nutrition;

• they may store carbohydrates as glycogen.

• Examples include Mucor, which has the typical fungal hyphal structure, and yeast, which is single-celled.

• Pathogenic fungal disease: Athletes foot

Describe the common features shown by eukaryotic organisms: protoctists

• These are microscopic single-celled organisms.

• Some, like Amoeba, that live in pond water, have features like animal cell, while others, like Chlorella, have chloroplasts and are more like plants.

• some are parasitic, some photosynthesise

• A pathogenic example is Plasmodium, responsible for causing malaria.

Describe the common features shown by prokaryotic organisms such as bacteria

• These are microscopic single-celled organisms;

• they have a cell wall, cell membrane, cytoplasm and plasmids;

• they lack a nucleus but contain a circular chromosome of DNA;

• some bacteria can carry out photosynthesis but most feed off other living or dead organisms. Examples include Lactobacillus, a rod-shaped bacterium used in the production of yoghurt from milk, and Pneumococcus, a spherical bacterium that acts as the pathogen causing pneumonia.

Describe viruses

• These are not living organisms.

• They are small particles, smaller than bacteria; they are parasitic and can reproduce only inside living cells;

• they infect every type of living organism.

• They have a wide variety of shapes and sizes; they have no cellular structure but have a protein coat and contain one type of nucleic acid, either DNA or RNA.

• Examples include the tobacco mosaic virus that causes discolouring of the leaves of tobacco plants by preventing the formation of chloroplasts, the influenza virus that causes 'flu' and the HIV virus that causes AIDS.

Give 4 different types of eukaryotic organism

Animal Plant Fungi Protoctist

Give 3 differences between plant and animal cells

• Plant cells have a cell wall whereas animal cells do not

• Plant cells have a permanent vacuole whereas animal cells do not

• Plant cells have chloroplasts and are able to photosynthesise whereas animal cells do not

Describe the structure of fungi

• Chitin cell wall

• Often multinucleated

• They contain a mycelium which is made of hyphae threads

How do fungi feed?

They are saprotrophic so they secrete enzymes that break down their food outside of their cells and then they absorb the nutrients.

Are prokaryotic cells multicellular or unicellular?

Prokaryotic cells are unicellular

Give 5 features of bacterium cells

• Cell membrane

• Cell wall

• Cytoplasm

• Plasmid loops of DNA

• No nucleus but large DNA loop instead

What is a pathogen?

A disease-causing microorganism

Give 4 different types of pathogen

bacteria, fungi, viruses, protoctists

Describe the structure of a virus

• Protein husk

• Contain nucleic acid (DNA or RNA)

Give 3 examples of viruses

• Tobacco mosaic virus (TMV)

• Human immunodeficiency virus (HIV)

• Influenza

Give two different species of bacteria

Lactobacillus bulgaricus - Used in the production of yoghurt from milk. Pneumococcus - Bacterium that causes pneumonia.