Ch. 4: Plant and Animal Cells Vocabulary: cell, organism, cell membrane, cytoplasm, nucleus, cell wall, chloroplast

Cells! When you look at a tiny kitten and a gigantic redwood tree, they might not seem like they have a lot in common at first, until you realize that both of them are made up of cells.

Discovering Cells In 1665, a scientist named Robert Hooke used a microscope to look at a thin strip of cork. He was amazed to see that the cork was made up of sections that he said looked like “tiny empty rooms.” He called these “tiny rooms” cells. Today, we know that all organisms are made of cells, and we also know that those cells are not empty.

Cell Parts Plant cells and animal cells pretty much have the same parts, with a few differences. All cells in both plants and animals have a cell membrane, cytoplasm, and a nucleus.

Cell Parts That is not to say that cells are simple, just that they both have some similar parts.

Cell Parts The major differences that need to be noted between the two cells, right now, are that plant cells have both a cell wall and chloroplasts.

Cell Parts Cell Membrane: It is located on the outside of the cell. It protects the other organelles from other cells and everything else in the outside world. Acts kind of like skin, except in most simple cells, water and food can pass through it.

Cell Parts Cytoplasm: The thick, gel like liquid inside a cell. Mostly made of water. Keeps the cell thick and puffy. Protects the other organelles inside the cell from bumping into each other and things in the outside world.

Cell Parts Nucleus: Controls all the cells activities. Not exactly like the brain of the cell, but sort of the boss. Contains the DNA of the cell and is used when the cell reproduces.

Special Plant Cell Parts Chloroplasts: Green organelles located inside the cell. They contain chlorophyll. Chlorophyll is the stuff that allows plant cells to turn light and carbon dioxide into energy (sugars).

Special Plant Cell Parts Cell Wall: Located on the outside of the plant cell, even outside the cell membrane. Thick and stiff, it acts like the skeleton of the plant. It’s what causes flowers and other plants, without bark, to be able to stand up by themselves without bones.

Special Animal Cells Unlike plant cells, which look mostly alike, animal cells look different based on the jobs that they do. These different cells all make up the stomach.

Questions about Chapter 4 1.Why did Hooke call the things he found “cells?” 2.What are the three parts that all cells have? 3.What are the two parts that only plant cells have? 4.What is the job of chlorophyll? 5.Why is the nucleus of the cell important? 6.Both the cell membrane and the cytoplasm protect the cell’s organelles differently. How do they work together?