Bacterial Cells, Specialized Cells, and Microscopy

This set covers bacterial cell components, specialized animal and plant cells and their adaptations, the principles of microscopy, and standard laboratory procedures and calculations for cell observation.

Pili

Short strands of hairlike things on some bacteria which aid movement.

Chromosomal DNA

Long coils of DNA found in bacterial cells.

Plasmid DNA

Small rings of DNA found in bacterial cells.

Slime capsule/coat

A structure found on some bacteria for protection.

Flagella

Structures on some bacteria that spin like a propeller for movement.

Specialised Cells

Cells differentiated into particular sub-cellular structures adapted to carry out a specific function.

Ciliated epithelial cells

Cells found in the airway of the throat to waft mucus or in the oviduct to waft egg cells to the uterus.

Cilia

Small hairs on a cell that help waft either mucus or egg cells.

Red blood cells

Cells found in the blood that transport oxygen around the body.

Biconcave shape

A dip in the outside of a cell that increases surface area for more oxygen absorption.

Haemoglobin

A molecule that gives red blood cells their red colour and stores oxygen.

Axons

Connections to other cells that give electrical signals.

Nerve cell

A cell located in the nerves that carries electrical impulses around the body.

Dendrites

Connections to another nerve cell that receive electrical signals between cells.

Sperm cells

Cells found in the testes that function to fertilise the egg cell.

Acrosome

A structure at the tip of the sperm head containing digestive enzymes to break down the egg cell membrane.

Haploid nucleus

A nucleus containing half the number of chromosomes ($23$) compared to a normal cell.

Diploid

Normal cells containing a full set of chromosomes ($46$).

Muscle Cells

Cells that contract and relax to help move the bones, containing special proteins for fiber contraction.

Egg cells

Cells found in the ovary with cytoplasm full of nutrients and a jelly coating for protection.

Root Hair cells

Cells in roots that absorb water and minerals using a large surface area and vacuole.

Palisade cells

Cells found in leaves with many chloroplasts to absorb sunlight for photosynthesis.

Microvilli

Finger-like extensions lining the small intestine that increase surface area for nutrient absorption.

Microscopy

The study of very small objects using an instrument called a microscope.

Magnification

How much bigger a sample appears under the microscope when compared to real life.

Resolution

The ability to distinguish between $2$ points, determining how clear an image is.

Light microscopes

Instruments that use light and lenses to magnify specimens, portable and able to see living organisms.

Electron microscopes

Instruments that use electrons to form an image with high magnification ($2,000,000\times$) and resolution.

Eyepiece lens

The lens closest to the eye with a magnification of $10\times$.

Objective lens

The lenses closest to the specimen with different powers to vary total magnification.

Coarse focusing dial

A large wheel used to move the objective lens or stage rapidly to get the specimen roughly into focus.

Fine focusing dial

A small wheel used for precision focusing to make the image sharp and clear.

Diaphragm

A part under the stage that rotates to adjust the amount of light passing through the specimen.

Iodine solution

A substance used to stain onion tissue yellow so it is easily viewed under a microscope.

Total Magnification Formula

$Eyepiece\,lens\,magnification \times Objective\,lens\,magnification$.

Magnification Equation

$$\text{Magnification} = \frac{\text{Image size}}{\text{Real size}}$$

Millimetre to Micrometre conversion

$$1\,mm = 1000\,\mu m$$

Micrometre to Nanometre conversion

$$1\,\mu m = 1000\,nm$$

Eukaryote

A cell that has its DNA in a nucleus and contains membrane-bound organelles.

Prokaryote

A cell that has free DNA (not in a nucleus) and no membrane-bound organelles.

Mitochondria

Sub-cellular structure that is the site of respiration and releases energy.

Ribosomes

The site of protein synthesis within a cell.

Permanent vacuole

A plant cell structure containing cell sap that provides shape and keeps the cell turgid.

Chloroplasts

Site of photosynthesis containing chlorophyll.

Cell wall

A structure made of cellulose that supports and provides shape to plant cells.