Cell Structures, Functions and Transport

Types of Cells Prokaryotic cells Eukaryotic cells

Prokaryotic cells Simplest cells No membranes around their nuclear material (DNA and RNA, genetic material) Prokaryotes include bacteria and some pond scum

Eukaryotic cells Eukaryotic cells have membranes around their nuclear material Membrane bound organelles Eukaryotes include protists, fungi, plants, and animals (almost all organisms)

Animal Cell Figure 7-5 Plant and Animal Cells Section 7-2 Go to Section:

Animal Cell Figure 7-5 Plant and Animal Cells Cell Membrane Section 7-2 Cell Membrane Go to Section:

Cell membrane

Eukaryotic Cell Organelles and Function Cell Membrane Nickname: “The Gatekeeper” Function: forms outer boundary of the cell allows only certain materials to move into and out of the cell Parts: made up of a double layer of fats with some proteins scattered throughout

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Cell Membrane Section 7-2 Cytoplasm Cell Membrane Go to Section:

Cell membrane Cytoplasm

Eukaryotic Cell Organelles and Function Cytoplasm Gel-like material inside the cell membrane and outside the nucleus Function: contains water, chemicals, and the various cell organelles Cytoplasm constantly moves or streams

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Nucleus Cell Membrane Nuclear Membrane Go to Section:

Cell membrane Cytoplasm Nucleus Nucleolus Nuclear envelope/membrane

Eukaryotic Cell Organelles and Function Nucleus Nickname: “The Control Center” Function: holds the DNA Parts: Nucleolus: dark spot in the middle of the nucleus that helps make ribosomes Nuclear envelope/membrane: surrounds nucleus in eukaryotic cells, has pores to let material in and out of the nucleus

Eukaryotic Cell Organelles and Function Nucleus Parts: Chromatin: Strands of genetic material found in the nucleus, made of protein and DNA

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Nucleolus Section 7-2 Cytoplasm Nucleolus Nucleus Cell Membrane Nuclear Membrane Mitochondria

Cell membrane Cytoplasm Nucleus Nucleolus Nuclear envelope/membrane Mitochondria

Eukaryotic Cell Organelles and Function Mitochondria Nickname: “The Powerhouse” Function: Energy formation Breaks down food to make ATP ATP: is the major fuel for all cell activities that require energy

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Nucleolus Ribosomes Nucleus Cell Membrane Nuclear membrane Mitochondria Go to Section:

Cell membrane Cytoplasm Nucleus Nucleolus Nuclear envelope/membrane Ribosomes Mitochondria

Eukaryotic Cell Organelles and Function Ribosomes Function: makes proteins Found in all cells, prokaryotic and eukaryotic

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Nucleolus Ribosomes Nucleus Cell Membrane Nuclear Membrane Mitochondria Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Go to Section:

Cell membrane Cytoplasm Rough Endoplasmic Reticulum Nucleus Nucleolus Smooth Endoplasmic Reticulum Nuclear envelope/membrane Ribosomes Mitochondria

Eukaryotic Cell Organelles and Function Endoplasmic Reticulum (ER) Nickname: “Roads” Function: The internal delivery system of the cell

Endoplasmic Reticulum 2 Types: Rough ER: Rough appearance because it has ribosomes on its surface Function: helps make proteins, that’s why it has ribosomes Smooth ER: NO ribosomes Function: makes fats or lipids

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Ribosomes Nucleolus Nucleus Cell Membrane Nuclear membrane Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Complex Go to Section:

Cell membrane Cytoplasm Rough Endoplasmic Reticulum Nucleus Nucleolus Smooth Endoplasmic Reticulum Nuclear envelope/membrane Ribosomes Golgi Body Mitochondria

Eukaryotic Cell Organelles and Function Golgi Complex (Golgi Body) Nickname: The shippers Function: packages, modifies, and transports materials to different location inside/outside of the cell Appearance: stack of pancakes Structure: stack of membrane-covered sacs

Animal Cell Figure 7-5 Plant and Animal Cells Cytoplasm Ribosomes Section 7-2 Cytoplasm Ribosomes Nucleolus Ribosomes Nucleus Cell Membrane Nuclear Membrane Mitochondria Smooth Endoplasmic Reticulum Rough Endoplasmic Reticulum Golgi Body Go to Section:

Cell membrane Cytoplasm Lysosome Rough Endoplasmic Reticulum Nucleus Nucleolus Smooth Endoplasmic Reticulum Nuclear envelope/membrane Ribosomes Golgi Body Mitochondria

Eukaryotic Cell Organelles and Function Lysosomes: circular, but bigger than ribosomes Nickname: “Clean-up Crews” Function: to break down food into particles the rest of the cell can use and to destroy old cells

Cell membrane Lysosome Cytoplasm Rough Endoplasmic Reticulum Nucleus Nucleolus Smooth Endoplasmic Reticulum Nuclear envelope/membrane Ribosomes Vacuole Golgi Body Mitochondria

Eukaryotic Cell Organelles and Function Vacuoles Function: Help store things Vacuoles in animal cells are usually small sacs

Animal Cell Cytoplasm Ribosomes Nucleolus Ribosomes Nucleus Cell Membrane Nuclear Membrane Mitochondria Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies Centrioles

Cell membrane Centriole (only 1 is shown) Lysosome Cytoplasm Rough Endoplasmic Reticulum Nucleus Nucleolus Smooth Endoplasmic Reticulum Nuclear envelope/membrane Ribosomes Golgi Body Mitochondria

Eukaryotic Cell Organelles and Function Centrioles Function: Help with cell division Only found in animal cells Look like two small bundles of spaghetti arranged perpendicular to each other

Now let’s talk about structures only found in PLANT Cells!!

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Cell Membrane Section 7-2 Vacuole Cell Membrane Go to Section:

Eukaryotic Cell Organelles and Function Vacuoles Function: stores water This is what makes lettuce crisp When there is no water, the plant wilts Animal cells have vacuoles to provide temporary storage Vacuoles in animal cells are smaller than plant vacuoles

Vacuole

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Go to Section:

Vacuole Chloroplast

Eukaryotic Cell Organelles and Function Chloroplasts Function: traps energy from the sun to produce food for the plant cell Green in color because of chlorophyll, which is a green pigment

Chloroplasts

Plant Cell Figure 7-5 Plant and Animal Cells Vacuole Chloroplasts Section 7-2 Vacuole Chloroplasts Cell Membrane Cell Wall Go to Section:

Cell wall

Eukaryotic Cell Organelles and Function Cell Wall Function: provides support and protection to the cell membrane Found outside the cell membrane in plant cells

Plant Cell Cytoplasm Vacuole Smooth ER Ribosomes Chloroplasts Rough ER Cell Membrane Cell Wall Nuclear Membrane Nucleolus Golgi Bodies Nucleus Mitochondria Rough ER

Cytoplasm Cell wall Lysosome Cell membrane Vacuole Rough ER Nucleus Nucleolus Smooth ER Nuclear envelope/membrane Ribosomes Chloroplast Golgi Bodies Mitochondria

Comparing Plant and Animal Cells

Comparing Plant and Animal Cells Cell Membrane Cytoplasm Nucleus Nucleolus Nuclear membrane Mitochondria Ribosomes Rough Endoplasmic Reticulum Smooth Endoplasmic Reticulum Golgi Bodies Lysosomes Vacuoles Cell Wall Chloroplasts Large vacuole Centrioles Small vacuole

It’s a question of control. Cell Transport It’s a question of control.

Who’s in control? Cells get nutrients, etc. from environment Release waste into same environment

Moving along…or not! Selective permeability: property of a cell membrane which allows some materials to pass through while keeping others out.

Diffusion Molecules move constantly Move from crowded conditions to less crowded conditions Particles diffuse in liquids and in gases

Diffusion cont’d Equilibrium: molecules of a substance are spread evenly throughout a space Molecules continue to move during equilibrium

Osmosis—Diffusion of H2O The diffusion of water through a cell membrane Most cells surrounded by water molecules and contain water molecules

Osmosis Cont’d What happened to egg cells in lab? If cells aren’t surrounded by pretty pure water, they’ll lose the water. No water molecules in corn syrup around eggs—so ….

Water tended to move out of the cells and dilute the corn syrup Cells became shriveled and yolks became firm

Place eggs in pure water and the process is reversed The eggs swell up and the yolks slosh around inside

Moving on… Particle movement across cell membrane by diffusion is called passive transport because… Cell doesn’t use energy to move the materials

Active transport: energy required to move large molecules through cell membrane Need help of transport proteins

Active transport is required to move substances from where there are small amounts to where there are large amounts

Cell membrane Cell membrane is composed of a double layer (bilayer) of phospholipids with protein molecules scattered throughout Phospholipids make a bilayer with polar heads facing out and hydrophobic tails facing in

Cell membrane model

Lipids