Biology

What is the function of the nucleus?

Contains the organism’s hereditary material, controls cell activities and manufactures ribosomal RNA and ribosomes

What is the function of the mitochondrion?

Site of aerobic respiration, produces ATP

What is the function of the chloroplast?

Carry out photosynthesis AND contain DNA to quickly manufacture proteins

What is the function of the rough endoplasmic reticulum?

Folds and processes proteins made on the ribosomes

What is the function of the smooth endoplasmic reticulum?

Synthesises, stores and transports lipids and carbohydrates, helps detoxification

What is the function of the golgi apparatus?

Modifies and packages lipids and proteins into vesicles to be transported to the cell membrane for excretion

What is the function of lysosomes?

Vesicles that contain hydrolytic enzymes which digest worn out organelles or pathogens

What is the function of ribosomes?

Site of protein synthesis

What is the function of the cell wall?

Provides support, prevents osmotic lysis, middle lamella acts as a natural glue, holding cells together

What is the function of the vacuole?

Makes cells turgid, acts as a temporary food store, contains anthocyanins

What are anthocyanins?

Pigments that attract pollinating insects

How do you study organelles?

Homogenation, Filtration, Ultracentrifugation, Sedimentation

What is homogenation?

Put cells in a blender to destroy the membrane and release the organelles

What is filtration?

Filter out bits of membrane

What is ultracentrifugation?

Organelles are separated by density (nucleus is densest)

What is sedimentation?

A sediment of the heaviest organelle is formed at different speeds, speed is increased for different organelle densities

What is a graticule?

A mini ruler on a microscope

What is a micrometre?

Thin sheet of plastic with measurements to accurately measure cells in a microscope

How is DNA stored in prokaryotic cells?

There is no true nucleus - DNA is loose in the cell and there are sometimes plasmids

What is the cell wall made of in prokaryotic cells?

Murein

What is the cell wall made of in eukaryotic cells?

Cellulose

What size are ribosomes in prokaryotic cells?

70S

What size are ribosomes in eukaryotic cells?

80S

What is a capsule?

The outer mucus covered layer some prokaryotic cells have

What is the function of the capsule?

Protects the bacterium from other cells and helps groups stick together

What is the function of plasmids?

Can help bacteria to survive in adverse conditions e.g. produces enzymes which break down antibiotics

What is a flagellum?

Tail/hair-like structure which some prokaryotes have

What is the function of flagellum?

Propels bacteria through liquid environments

What is this?

A virus

What is this?

A bacterium

What is this?

An animal cell

What is this?

A plant cell

What is the magnification of a light microscope?

up to 1500x

What is the magnification of a TE microscope?

up to 1,500,000x

What is the magnification of an SE microscope?

up to 1,500,000x

How does a light microscope work?

Light is passed through the specimen and a pair of convex glass lenses are used to bend and magnify the light rays

How does a TE microscope work?

A beam of electrons is fired at the specimen, areas that absorb the electrons appear darker

How does an SE microscope work?

Electrons scatter across the surface and the pattern of scattering makes a 3D image

What is the image formed from an electron microscope called?

electron micograph

What are the limitations of light microscopes?

lower magnification and resolution, staining may introduce artefacts, 2D image produced

What are the limitations of TE microscopes?

expensive, complex training, dead specimens (vacuum), staining may introduce artefacts, specimen must be sliced thinly, 2D image produced

What are the limitations of SE microscopes?

expensive, complex training, dead specimens (vacuum), staining may introduce artefacts, lower resolving power than TEM

What is magnification?

How many times bigger an image of a specimen is compared to its actual, real-life size

What is resolution?

The ability to distinguish between two distinct separate points

What is the formula for magnification?

magnification = size of image / size of real object

What is a capsid?

Contains DNA or RNA in viruses

What are attachment proteins?

Viruses have them to attach to host cells

What is a virus?

A non-living, acellular infectious particle that relies entirely on a host cell to replicate

What is an optical microscope?

Light microscope

What are some adaptations of an immune cell?

Phagocytes have a flexible cell membrane to trap pathogens outside

What are some adaptations of epithelial cells?

Microvilli to increase surface area so more nutrients can be absorbed into the bloodstream, many mitochondria and one cell thick

What are some adaptations of nerve cells?

long axon to allow for fast communication (less synapses), myelin sheath has breaks in it o impulses travel faster

What are some adaptations of blood cells?

biconcave, no nucelus, flexible to fit through blood vessels

What are some adaptations of bone cells?

Lots of endoplasmic reticulum to fold and package proteins needed to make bone

What are some adaptations of fat cells?

Large lipid droplet - lots of space for storage

What are some adaptations of muscle cells?

Lots of mitochondria, store glycogen for quick release of energy