Cell Biology Flashcards

Eukaryotic cell

A cell that has a nucleus (eg. plant, animal, fungal)

Prokaryotic cell

A cell that has no nucleus (eg. bacteria)

Cell membrane

Controls what goes in and out of the cell

Nucleus

Stores the DNA and controls the cell

Cytoplasm

A jelly like substance where most of the chemical reactions happen

Mitochondria

Provides the cell with energy (respiration)

Ribosomes

Synthesises proteins

Cell wall

Made up of cellouse and supports the structure of the plant cell

Chloroplast

Contains a green pigment called chlorophyll and is used for photosynthesis

Vacuole

Stores cell sap and supports the cell

Why must the layer of onion cells be so thin?

To make them more visible under the microscope

Why must you lower the coverslip at an angle?

To prevent air bubbles from getting trapped, which could block or distort the view of the cells

How can a student make the blurred image of the cells look sharper?

Use the fine focusing knob until the image comes into a clear, sharp focus

Give two advantages of using an electron microscope compared to the light microscope.

Electron microscopes have a higher magnification and a higher resolution

When looking at a onion’s epidermis, what sub-cellular structure can you see through the microscope?

Nucleus, Cytoplasm, Cell wall, Cell membrane

Magnification

How many times larger the image is than the real object

Resolution

When you are able to distinguish 2 objects that are very close together as separate objects

Bacterial Chromosome

Contains the essential DNA of bacteria

Plasmids

Small rings of DNA that contains adaptations (eg. antibody resistance)

Magnification formula

Magnification = image size / real size

Coarse focus Knob (microscope)

Brings specimen into a rough focus

Fine focus Knob (microscope)

Brings specimen into a clear focus

Sperm Cell

Function: to fertilise egg cell to produce embryo

Adaptation: lots of mitochondria for energy, half DNA, acrosome with enzymes to digest egg cell membrane, flagellum to swim, streamlined shape

Cilliated Epithelial Cell

Function: trap dust in the respiratory system (eg. trachea, bronchi)

Adaptations: lots of mitochondria, little hairs extensions (cillia) that sway to trap mucus

Red Blood Cell

Function: to store / collect oxygen and carbon dioxide to and from other cells and tissues

Adaptations: no nucleus for more space, red pigment haemoglobin to store oxygen, bio-concave disc shape for maximum space, small to squeeze through capillaries and arteries

Xylem Cells

Function: part of the transport system and transports water and minerals

Adaptations: made from lignin, no cytoplasm, long hollow tubes, made from dead cells

Muscle Cells

Function: controls movement in the body

Adaptations: can contract (get short and fat) and relax (get long and thin), lots of mitochondria for energy, long

Root Hair Cell

Function: absorbs water and minerals in the soil

Adaptations: large extension for larger surface area, large vacuole for store, and thin cell wall so diffusion is easier, no chloroplasts

Palisade Cell

Function: for photosynthesis of the plant

Adaptations: long and narrow so for maximum amount of cells to capture sunlight, lots of chloroplasts, large vacuole, rigid cellouse cell wall for structure

Egg Cell

Function: to produce a foetus after fertilisation

Adaptations: half DNA, lots of mitochondria and cytoplasm, big

Phlem Cell

Function: transports dissolved glucose

Adaptations: like a vein, long and hollow, made up of living cells unlike xylem cells

Nerve Cell

Function: transports electrical pulses in the brain

Adaptations: stretched cytoplasm to form axons made from a fatty sheath (myelin), nerve endings are long and thin (dendrites)