Cell Biology Review

Learning Target:Identify key ideas in cell biology you need to study

for test on Tuesday!

1. Explain what cells are and why they are important to learn about.

• Building blocks of life, what all living things are made of.• Helps us better understand how our bodies work, how

living things work, help cure diseases.

2. Explain two key differences between prokaryotic and eukaryotic cells. Give examples of each.

• Eukaryotic cells have nuclei, prokaryotic don’t.• Eukaryotic cells bigger, more complex.• Prokaryotic: bacteria• Eukaryotic: animal, plant

3. Describe the function and importance of the following:

a. nucleus –

b. DNA –

c. cell membrane –

d. cytoplasm –

e. ribosome –

f. mitochondrion –

g. chloroplast –

h. cell wall -

“brain” of the cell, controls cell activities and contains DNA.

Contains genetic information. Determines what you look like.

“skin” of the cell. Controls what goes in & out.

Liquid part of cell between nucleus & cell membrane. Where most cell activities happen.

Make proteins.

Breaks down sugar to release energy. “Powerhouse.”

Where photosynthesis happens in plant cells. How plants make food (sugar).

Thick outer covering of plant cells. Provides support and protection.

4. Identify two cell structures found in plant cells but not in animal cells. Explain why they are of particular importance to plants.

• Chloroplasts, cell wall.• Without chloroplasts, plants couldn’t make own

food.• Without cell walls, plants wouldn’t be able to grow

tall enough to reach sunlight.

5. Draw a simple animal cell diagram and label the following: nucleus, DNA, cytoplasm, cell membrane, mitochondrion, ribosomes.

Organelle Functions Analogy

mitochondria “Powerhouse of cell”, where glucose is broken down to get energy

Power plant, electricity generator

Animal Cell Plant Cell

6. Draw a simple plant cell diagram and label the following: cytoplasm, cell membrane, cell wall, mitochondrion, chloroplast.

Organelle Functions Analogy

chloroplasts Where photosynthesis happens, where food is made in plant cells.

Kitchen, farm, cafeteriaSolar panels

Animal Cell Plant Cell

7. Explain what photosynthesis is and why it is important to all life on Earth.

• The way plants use light energy to make food in the form of sugar (glucose).

• Photosynthesis at beginning of almost every food chain on Earth.

Hydrothermal vent

8. Describe the function of protein channels in the cell membrane.

Provide passageways for larger molecules to get through cell membrane.

Proteinchannel

9. Define diffusion. Give an example of how you may see diffusion happen in your every day life….

• Movement of molecules from area of high concentration to low.

• Fart diffuses through crowded room……

10. Define equilibrium. Give an example of how you may see equilibrium in your every day life….

• Equal concentration of molecules all over.• Fart spread equally throughout room……

11. Use words and pictures to explain why it is easier for glucose molecules to get into cells than starch molecules.Glucose (sugar) molecules small enough to fit through protein channels. Starch molecules too big. Have to be broken down into sugar.

Glucose(sugar)

starch

12. Use words and pictures to explain how osmosis causes an animal cell to change size in pure water and in salt water.

Higher concentration of water outside than in, so more molecules move into cell than go out. This makes cell swell (get bigger).

Pure water (100% water) salt water (70% water)

Higher concentration of water inside than out, so more molecules move out of cell than in. This makes cell shrink.

80% water 80% water

What’s the difference between osmosis and diffusion?

• Diffusion = movement of molecules from area of high concentration to low.

• Osmosis = diffusion of water across a membrane.

Red food coloring diffuses through a glass of water

Water moves by osmosis from left to right

Equilibrium(equally spread out)

Water tends to move in or out of cells by osmosis in such a way as to reach equilibrium (equal concentrations inside and outside)

Osmosis Animation

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__how_osmosis_works.html

http://highered.mheducation.com/sites/9834092339/student_view0/chapter38/animation_-_osmosis.html

• Active requires energy from cells, passive doesn’t. • Diffusion: passive.• Moving stuff from low concentration to high: active.

13. Explain the difference between active and passive transport in cells. Give examples of each.

High concentrationLow concentration

1. Rolling ball downhill is like _________ transport.2. Rolling ball uphill is like ____________transport.

Cell membrane

passive

Concentration gradient

High concentrationLow concentration

1. Rolling ball downhill is like _________ transport.2. Rolling ball uphill is like ____________transport.

Cell membrane

passive

Concentration gradient

High concentrationLow concentration

1. Rolling ball downhill is like _________ transport.2. Rolling ball uphill is like ____________transport.

Cell membrane

passiveactive

Concentration gradient

High concentrationLow concentration

1. Rolling ball downhill is like _________ transport.2. Rolling ball uphill is like ____________transport.

Cell membrane

passiveactive

Concentration gradient

Active or passive?

Questions?