Science - Ch. 1 Lessons 1-4: 7th Grade

Cell theory

A widely accepted explanation of the relationship between cells and living things

Cell wall

A rigid structure that surrounds the cell membrane and provides support to the cell

Nucleus

acts as a cell's control center, directing all of the cell's activities.

Multicellular

Made up of more than one cell.

Compound

form when two or more elements combine chemically.

Element

A substance that cannot be broken down into simpler substances

Lysosome

contains substances that break down large food particles into smaller ones

Osmosis

the diffusion of water molecules across a selectively permeable membrane

Tissue

A group of similar cells that perform a specific function.

Organ system

A group of organs that work together to perform a major function.

Chloroplast

Captures energy from sunlight and changes it to a form of energy cells can use in making food.

Organelle

carries out specific functions within a cell

Passive transport

The movement of dissolved materials across a cell membrane without using the cell's energy.

Golgi Apparatus

receives proteins and other newly formed materials from the ER, packages them, and distributes them to other parts of the cell or to the outside of the cell

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Ribosome

small grain-shaped organelles that produce proteins

What is the organization of your body?

cell, tissue, organ, organ system, organism

Endocytosis

the cell membrane changes shape and engulfs the particle

Exocytosis

reverse of endocytosis which allows large particles to leave a cell.

What is DNA?

is the genetic material that carries information about an organism and is passed from parent to offspring. This information directs a cell's functions.

Shape of DNA

The shape of a DNA molecule is described as a double helix or a twisted ladder.

Examples of Compounds

carbon dioxide, H2o

Name 2 things water is useful for

It helps keep cells their shape. It also helps keep the temperature of cells from changing rapidly