Cell Structures and FunctionsGuided Notes – Part 2

What you should already know…• A prokaryotic cell is a cell

that does not have a nucleus, such as bacteria and archaea.

• Prokaryotes are single-celled organisms that do not have a nucleus or membrane-bound organelles.

What you should already know…• A eukaryotic cell is a cell

that contains a nucleus, such as plant and animal cells.

• Eukaryotes are organisms made of eukaryotic cells.

• Eukaryotes can be single-celled, but many are multicellular.

Bacteria

• The most common prokaryotes, and the smallest cells known.

• Bacteria have – ribosomes– web-like cell wall– cell membrane– long, circular DNA– flagellum (for movement)

Eukaryotic Cells

• Plant cells and animal cells are two types of eukaryotic cells.

• They have many cell parts in common, but also have cell parts that are different.

Eukaryotic Cells

• A eukaryotic cell has many parts that perform functions to help the cell stay alive.

-cell membrane -cell wall-cytoskeleton -nucleus-ribosomes -mitochondria-endoplasmic reticulum -chloroplasts-Golgi complex-cell compartments (vesicles,

lysosomes, vacuoles)

Cell Membrane

• All cells have a cell membrane, a protective barrier that encloses a cell.

• It separates the cell’s contents from the cell’s environment.

• The cell’s membrane contains proteins, lipids, and two layers of phospholipids.

Cell Wall

• A rigid structure that gives support to a cell.

• Plants and algae have cell walls made of cellulose.

• Fungi, including yeasts and mushrooms, also have cell walls made of chitin.

• Prokaryotic cells have cell walls, but they are different from plants and fungi.

Cytoskeleton

• A web of proteins in the cytoplasm, that acts as both a muscle and skeleton.

• It keeps the cell’s membranes from collapsing.

• Made of protein, and helps some cells move

Nucleus• A large organelle in eukaryotic

cells that contains the cell’s DNA, or genetic material.

• DNA contains the information on how to make proteins, which control the chemical reactions and provide structural support for cells and tissues.

• The nucleus is covered by two membranes.

Ribosomes

• Organelles that make proteins.

• The most abundant and the smallest of all organelles.

• All cells need proteins to live.

• Proteins are made of amino acids.

Endoplasmic Reticulum• A system of folded membranes in

which proteins, lipids, and other materials are made.

• The ER is part of the internal delivery system of the cell where substances move through the ER to different places in the cell.

• ER is either smooth or rough.

• Rough ER is covered by ribosomes, which make proteins.

• Smooth ER makes lipids and breaks down toxic materials that could damage the cell.

Mitochondria

• Organelles in which sugar is broken down to produce energy.

• Energy released by mitochondria is stored in a substance called ATP, which the cell then uses to do work.

• Mitochondria are covered by two membranes.

Chloroplasts

• Organelles in plant and algae cells in which photosynthesis takes place, the process by which plants and algae make their own food.

• Chloroplasts are green because they contain chlorophyll.

Golgi Complex• The organelle that packages and

sends out proteins.

• Looks like the smooth ER.

• Lipids and proteins from the ER are delivered to the Golgi complex, where they may be modified to do different jobs.

• The final products are enclosed in a piece of the Golgi complex’s membrane, that pinches off and then transports to other parts of the cell or out of the cell.

Cell Compartments - Vesicles• Vesicles are small sacs

that surround materials to be moved into, within, or out of the cell.

• All eukaryotic cells have vesicles.

Cell Compartments - Lysosomes• Lysosomes are vesicles

that are responsible for digestion inside a cell.

• They contain digestive enzymes that destroy worn-out or damaged organelles, get rid of waste materials, and protect the cell from foreign invaders.

Cell Compartments - Vacuoles• In plant and fungal cells,

some vacuoles act like lysosomes.

• The large central vacuole in plant cells stores water and other liquids.

• Animal cells have small vacuoles that aid in digestion and the release of waste products.

Organization of Living Things

Tissues

• A tissue is a group of cells that work together to perform a specific job.

• Example – cardiac muscle tissue

• Animals have four basic types of tissues:– nerve tissue– muscle tissue– connective tissue– protective tissue

Organs

• A structure that is made of two or more tissues working together to perform a specific function.

• Examples – heart, stomach, intestines, brain.

Organ Systems

• A group of organs working together to perform a particular function.

• Each organ system has a specific job to do in the body.

• Example – digestive system• Plants also have organ

systems – leaf systems, root systems, and stem systems.

Organisms

• Anything that can perform life processes by itself.

• They can be either unicellular or multicellular.

• Organ systems work together to form organisms.

Review

• Choose 4 cell structures and describe the function for each.

• Describe 3 ways in which plant cells differ from animal cells.

• Explain why every cell needs ribosomes.

• Identify the levels of organization in living things.