Science 8 Unit 2 Topics 1-3

cell theory

All living things are composed of one or more cells, Cells are the basic unit of structure and function in all organisms.

Level of Cell Organization

System ➔ Organ ➔ Tissue ➔ Cell

Why are cells so small

They would be very inefficient if they were large. Larger cells would need more materials and would produce more waste.

Cell Wall

a rigid structure surrounding the cell membrane of plants, fungi, and some unicellular organisms; protects and supports the cell

Organelles

a structure within a cell that has specific function

eyepiece

also called the ocular lens - used to look through, and the lens magnifies an object

Chloroplasts

an organelle that contains chlorophyll and enables plants to make carbohydrates through the process of photosynthesis; found only in plants and in some unicellular organisms

characteristics of all living organisms

are made of cells need energy grow and develop respond to their environment reproduce have adaptations for their environment produce wastes

functions all living organisms

energy movement reproduction growth wastes

Unicellular

having a single cell

Multicellular

having many cells

Vacuoles

in a cell, a fluid-filled organelle that stores water, food, wastes, and other materials

Nucleus

in a cell, an organelle that controls all the cell's activities

field of view

is the area you see when you look through a microscope

coarse adjustment knob

moves the tube up and down, to help focus the lens - like a camera lens

Cytoplasm

the gel-like substance within the cell membrane that contains and supports the structures of the cell

Cell Membrane

the selectively permeable structure enclosing the contents of a cell or organelle; regulates the passage of substances into and out of a cell or organelle

Cellulose

the tough, carbohydrate material that in large part makes up the cell walls of many plants and fungi

the diaphragm

use to change the amount of light that shines on the slide

the stage

where you place the slide; it has clips so the side doesn't move and it has a hole in the center which allows a light to brighten up the slide