Science Unit 1.0

STUDYSTUDYSTUDY

Cell Theory

1. Cells are the basic units of life 2. Organisms can be unicellular, or multicellular. 3. All cells are created from existing cells through cell division.

Compound Light Microscope

A microscope that uses light focussed through several different lenses to form a magnified image of a specimen.

Eye Piece/Ocular Lens

The lens that magnifies the specimen, usually by 10x.

Coarse Adjustment Knob

The knob that moves the stage up or down to focus on the specimen. Use this before using the fine adjustment knob.

Fine Adjustment Knob

Lens that sharpens images under low and medium power. It is the only knob needed with the high-power lens.

Revolving Nosepiece

Where the objective Lenses are mounted. Rotates the lens to select low power (4x), medium power (10x), and high power (40x).

Objective Lenses

Has three lenses that magnify the specimen; low, medium, and high power.

Stage

Where you place a slide for observation. Always keep the stage dry.

Stage Clips

Used to hold a slide in position on the stage.

Diaphragm

Has different holes that let amounts of light pass through the specimen on the stage.

Lamp

Supplies the light that passes through the specimen on the stage. Microscopes that don't have a lamp may have a mirror to collect and direct light.

Tube

Separates the ocular lens from the objective lenses at a distances calculated for proper magnification.

Condenser Lens

The lens under the stage. It helps focus light onto the specimen on top of the stage.

Cytoplasm

A Jelly-like material that fills the cell and surrounds the organelles. Food and oxygen move through the cytoplasm to the organelles.

Cell Membrane

A thin covering allowing only certain materials in or out. It also holds the cytoplasm.

Organelles

Tiny parts within the cell that have special functions that help the cell survive, grow, and reproduce.

Membrane (Organelle Membrane)

Keeps different parts of the cell separate from one another.

Endoplasmic Reticulum

A folded organelle that makes proteins.

Golgi Apparatus.

A folded organelle that combines proteins made by the endoplasmic reticulum and delivers them to the rest of the cell and outside the cell.

Mitochondria

The powerhouses of the cell. These membrane-bound organelles break down food particles and release their stored energy. The cell uses this energy to fuel all of its activities.

Vacuole

A large, sac-like organelle that stores excess food, waste, and other substances. They are membrane-bounded

Chloroplasts (Only in plant cells)

Membrane-bound organelles that contain a green substance called chlorophyll. (Only found in plant cells)

Chlorophyll (Only in plant cells)

Uses the sun's energy to convert carbon dioxide and water into sugar and oxygen.

Nucleus

A large organelle that is easy to see under magnification. It acts as the brain of the cell, and controls it's activities, such as growth.

Cell Wall (Only in plant cells)

The rigid structure that surrounds the cell membrane. It provides the cell with strength and support. Materials pass in or out of the cell through the pores of the cell wall.

Ribosomes

Tiny Organelles that help make protein. There are many of these organelles in the cytoplasm.

Lysosomes

Organelles that break down food and digest wastes.

Why are cells stained?

Because they do not have much colouring, so light passes through them.

Micrograph

A photograph taken with a microscope.

Permeable

Allowing liquids or gases to pass through easily.

Impermeable

Not allowing fluids to pass through.

Selectively Permeable

Only allowing certain substances to pass through it.

Cellular Transport

The movement of substances into and out of a cell. This involves several different processes, such as diffusion and osmosis.

Diffusion

The movement of particles from an area of high concentration to an area with lower concentration. This continues until both areas have the same concentration. For a cell, diffusion is how resources are transported into it through its selectively permeable membrane.

Osmosis

A special kind of diffusion that involves water moving from an area of higher concentration of water to an area of lower concentration of water through a selectively permeable membrane.

Osmosis in cells (explained)

In cells, if the concentration of water particles is higher than it is outside the cell, water will move outside the cell by osmosis. If the concentration of water particles outside is higher, the water particles will move into the cell.

Concentration

The measure of how much of a given substance there is mixed with another substance.