The Cell Mrs. Womack

Cell Shape and Movement The size and shape of a cell relates to its job or function The structures that make up a cell also have unique functions

Cell Membrane Cell membrane – is a flexible covering that protects the inside of a cell from the environment outside the cell Cell membranes are mostly made up of 2 different macromolecules – proteins and phospholipids.

Cell Wall Cell wall - a stiff structure outside the cell membrane Composed mainly of carbohydrates, such as cellulose Protects the cell from attack by viruses and other harmful organisms In plant cells and fungal cells the cell wall helps maintain the cell’s shape and gives structural support

Cytoplasm Cytoplasm – a fluid inside a cell that contains salts and other molecules Also contains the cell’s cytoskeleton Cytoskeleton – a network of threadlike proteins that are joined together The proteins form a framework that gives the cell its shape Cilia and flagella – made from same proteins as cytoskeleton

Cell Appendages Flagella – long, tail-like appendages that whip back and forth and move a cell Cilia – short, hair-like structures. They move molecules away from a cell Ex: cilia in your windpipe move harmful substances away from your lungs

Cell Types Prokaryotic cells – the genetic material is not surrounded by a membrane – this is the most important feature of a prokaryotic cell Do not have many of the other cell parts as other cells Most are unicellular organisms and are called prokaryotes

Cell Types Eukaryotic cells – plants, animals, fungi, and protists are made of eukaryotic cells Surrounded by a membrane Every eukaryotic cell has other structures called organelles Organelles – have specialized functions and are surrounded by membranes About 10 prokaryotic cells would fit inside one eukaryotic cell

Prokaryote vs Eukaryote

Cell Organelles Nucleus – part of a eukaryotic cell that directs cell activities and contains genetic information which is stored in the DNA DNA is organized into structures called chromosomes The number of chromosomes in a nucleus is different for different species of organisms Humans – 23 pairs of chromosomes

Cell Organelles Nucleus – contains proteins and an organelle called the nucleolus Nucleolus – make ribosomes which are involved in the production of proteins Surrounding the nucleus are 2 membranes that form a structure called the nuclear envelope which contains pores The pores allow RNA and ribosomes to move into and out of the nucleus

Manufacturing Molecules Proteins are made on the ribosomes Ribosomes are not surrounded by a membrane Ribosomes are located in a cell’s cytoplasm They can be attached to the endoplasmic reticulum (ER)– a web-like organelle The ER with ribosomes is called the Rough Endoplasmic Reticulum

Manufacturing Molecules Smooth Endoplasmic Reticulum – ER without the ribosomes Smooth ER makes lipids such as cholesterol and helps remove harmful substances from a cell

Processing Energy All living things require energy to survive Most eukaroytic cells contain hundreds of organelles called mitochondria Mitochondria – found in eukaryotic cells, is surrounded by 2 membranes. Energy is released during chemical reactions in the mitochondria This energy is stored in high-energy molecules called ATP (adenosine triphosphate) ATP – the fuel for cellular processes such as growth and cell division

Processing Energy Chloroplasts – membrane-bound organelles that use light energy and make food – a sugar called glucose – from water and CO2 in a process called photosynthesis Plant cells and some protists, such as algae, contain chloroplasts

Processing, Transporting, and Storing Molecules Golgi apparatus – prepares proteins for their specific jobs or functions Then it packages the proteins into tiny, membrane-bound, ball-like structures called vesicles Vesicles transport substances from one area of a cell to another Some vesicles are called lysosomes

Lysosome

Golgi Apparatus

Processing, Transporting, and Storing Molecules Lysosomes contain substances that help break down and recycle cellular components Vacuoles – a saclike structure that stores food, water, and waste material A typical plant cell has one large vacuole, animal cells contain many vacuoles