Movement: can change position 

Reproduction: can have offspring either sexually or asexually 

Sensitivity: can detect stimuli, such as light, and respond to them Control: can control their internal environment (homeostasis) 

Growth: can increase mass 

Respiration: can produce energy either aerobically or anaerobically

 Excretion: can remove toxic or waste produced by reactions in the body 

Nutrition: can absorb nutrients in order to use them for growth and repair 

These can be remembered under the acronym of MRS C GREN.

Structure Function 

Nucleus 

● Contains the genetic material, which codes for a particular protein 

● Enclosed in a nuclear membrane. 

Cytoplasm 

● Liquid substance in which chemical reactions occur. 

● Contains enzymes (biological catalysts, i.e. proteins that speed up the rate of reaction). 

● Organelles are found in it 

Cell membrane

 ● Contain receptor molecules to identify and selectively control what enters and leaves the cell Mitochondria

 ● Where aerobic respiration reactions occur, providing energy for the cell Ribosomes 

● Where protein synthesis occurs. 

● Found on a structure called the rough endoplasmic reticulum.

Plants 

● E.g. cereals (such as maize) or herbaceous legume (such as peas) 

● Multicellular organisms 

● Cells contain chloroplasts which is the site of photosynthesis: chlorophyll pigments within the chloroplast structure absorb light from the Sun 

● Cellulose cell walls which provide strength to the cell

 ● Contain a permanent vacuole, which stores cell sap and improves the cell’s rigidity 

● Store carbohydrates as starch or sucrose 

Animals

 ● E.g. mammals (such as humans) and insects (such as flies) 

● Multicellular

 ● Cannot photosynthesise 

● Do not have cell walls 

● Have nervous systems in order to coordinate movement 

● Store carbohydrates as glycogen 

Fungi 

● Body is usually organised into a mycelium of thread-like structures called hyphae which have many nuclei but some are single-celled

● E.g. Mucor has typical hyphal structure, yeast is single-celled 

● Cell walls are made of chitin 

● Feed by extracellular secretion of digestive enzymes which break it down into smaller pieces, which can then be absorbed (saprotrophic nutrition) 

● May store carbohydrates as glycogen 

Protoctists 

● Single-celled organisms 

● Some have features like animals cells, such as Amoeba, that live in pond water

 ● Others are more like plants and have chloroplasts, such as Chlorella 

Prokaryotes (1.3)

 Prokaryotes do not have a nucleus or membrane-bound organelles 

Bacteria 

● E.g. Lactobacillus bulgaricus (rod-shaped bacterium used to make yoghurt), Pneumococcus (spherical bacterium that causes pneumonia)

 ● Single-celled and very small 

● Have a cell wall, cell membrane, cytoplasm and plasmids

 ● Lack a nucleus but have circular chromosomes of DNA

 ● Some can carry out photosynthesis but they mainly eat off of other organisms, either dead or alive 

Pathogens (1.4) 

Pathogens are disease-causing organisms and can be fungi, bacteria, protoctists or viruses. Viruses 

● E.g. tobacco mosaic virus which prevents chloroplast formation, influenza virus, HIV virus leading to AIDS 

● Viruses are small particles (much smaller than bacteria) - not living organisms 

● Parasitic 

○ Can only reproduce within living cells 

○ Can infect every type of living organisms

 ○ Hijacks the cell mechanisms to create millions of copies of itself and then spreads within the host by cell bursting 

● They come in a wide variety of shapes and sizes 

● Do not have a cellular structure but have one type of nucleic acid (either DNA or RNA) and a protein coat 

Bacteria 

● E.g. Salmonella (food poisoning)- caused by salmonella- rod shaped bacteria

●E.g Pneumonia-caused by Pneumococcus-spherical shaped bacteria

● Can reproduce many times through binary fission

● Produce toxins that can damage cells 

Protists 

● E.g. malaria- caused by plasmodium

• Eg Cholera-caused by cholera

● Parasitic - use animals as their hosts to live in 

Fungi 

● E.g. Athlete’s foot 

● Produce spores that can spread in the wind or between people 

● Can treat with fungicides/Antibodies