Biology - Nature and Variety of Living Organisms

Eukaryotes

They have a nucleus

Prokaryotes

They don’t have a nucleus

Movement

In simple living organisms, the living parts of the cell, protoplasm, will move. In more complex organisms, either the whole structure or the whole organism will move

Respiration

Living organisms are able to break down sugars to release energy contained for their own purposes

Sensitivity

Living things are able to recognise and respond to changes in their external and internal environment

Homeostasis

Making sure the internal conditions of the organism are at suitable level for survival, for example regulating the temperature

Growth

Either the amount of protoplasm within a cell will increase or in multicellular organisms, the number of cells will increase

Reproduction

Living organisms are able to increase numbers in order to maintain the species

Excretion

Organisms eliminate waste products from their chemical processes

Nutrition

Organisms take in the materials necessary for energy release, growth and the manufacture of substances. Autotrophs make their own food. Heterotrophs take in food

Autotrophs

They make their own food. e.g. plants, bacteria and protoctis

Heterotrophs

They take in food. e.g. animals, fungi, bacteria and protoctis

Animal cell

Ribosome, nucleus, mitochondria, cell membrane, cytoplasm

Plant cell

Cell wall (made of cellulose), cell membrane, nucleus, chloroplasts, ribosomes, permanent vacule, mitochondria, cytoplasm

Yeast cell

Ribosome, nucleus, mitochondria, cell membrane, cytoplasm, vacuole, cell wall (made of chiton)

Bacterium cell

Cytoplasm, cell membrane, cell wall (made of peptidoglycan), nucliod, cell capsule, plasmid, flagellum

Fungi cell

Spores, sporengium, aerial hyphae, mycelium, nucleus

Protoctis cell

Ribosome, nucleus, mitochondria, cell membrane, cytoplasm

Virus

Nucleic acids, protein coat, attachment proteins

Ribosome

Site of protein synthesis

Nucleus (nucliod on bacterium cell)

Contains DNA

Mitochondira

Site of aerobic respiration. Release energy (ATP) for the cell to use

Cell membrane

Controls what goes in and out of the cell

Cytoplasm

Where chemical reactions occur within the cell

Cell wall

Gives the cell rigidity and strength

Chloroplasts

The site of photosynthesis, produces glucose for the plant to use in respiration

Permanent vacuole

Storage for nutrients, provides shape and strength for the cell

Cell capsule

Protects from engulfment by eukaryotic immune cells, desiccation and helps bacteria adhere to surfaces

Plasmid

Carry genes for replicating their DNA

Flagellum

Involved in the locomotion of a cell

Spores

Allows fungi to reproduce

Sporengium

Produces spores, mitosis

Aerial hyphae

Release enzymes and absorb nutrients from a food source

Mycelium

Absorbs nutrients and food from the environment

Nucleic acids

Storage and expression of genomic information

Protein coat

A shell to protect the viral genome from nucleases and when during infection attaches the variant to the specific receptors exposed on the prospective host cell

Attachment proteins

The ‘key’ that unlocks host cells by interacting with the ‘lock’ - the receptor - on the cell surface

Differences between bacterium cells and viruses

Bacteria is a living organism but viruses are not. Bacteria = free-living, single cells that can survive on their own, inside or outside the body. Viruses = non-living collection of molecules that need a host to survive

Animals

Multicellular organism

Don’t contain chloroplasts and are not able to carry out photosynthesis

Don’t have cell walls

Usually have nervous co-ordination and are able to move from one place to another

Store carbohydrates as glycogen

Plants

Multicellular organisms

Contain chloroplasts and are able to carry out photosynthesis

Cell walls are made of cellulose

Carbohydrates are stored as starch or sucrose

Fungi

Not able to carry out photosynthesis

Some are single-celled (yeast) whilst others are multicellular (mushroom)

Multicellular fungi consists of a body called mycelium

The mycelium is a web of thread like structures called hyphae which contain many nuclei

Fungus cell walls are made of chiton

They either gain nutrition by feeding off other organisms (living as parasites) or by decaying ready-formed organic matter (living as saprophytes)

Bacteria

Microscopic single-celled organisms

Have cellular structure but do not have a true nucleus

Some are able to carry out photosynthesis

Most gain nutrients from feeding off other dead or living organisms

Some are pathogens (cause disease) but not all

Many are free-living (e.g. decay causing species)

Protoctis

Microscopic single-celled organisms

All have cellular structure including a true nucleus

Some have features like an animal cell e.g. Amoeba

Others have chloroplasts and are more like plants e.g. Chlorella (algae)