College Biology - Cell Unit

Test 3

Types of Cells

Prokaryote (bacteria)

Eukaryote (plant and animal)

How many layers in a bacteria cell?

3 layers

1. Cell membrane

2. Cell wall

3. Capsule

Bacteria Cell Characteristics

DNA (scribble near top)

Ribosomes (dots)

Cilia (hairs)

Flagella (tail)

How many layers in a plant cell?

2 layers

1. Cell membrane

2. Cell wall

Plant Cell Characteristics

Nucleus

Cytoplasm

Mitochondria

Ribosomes

Chloroplasts (plants)

Central Vacuole (plants)

Golgi

ER (SER and RER)

Vesicles (bubbles)

How many layers in a animal cell?

1 layer

1. Cell membrane

Animal Cell Characteristics

Nucleus

Cytoplasm

Mitochondria

Ribosomes

Lysosomes (animals)

Food Vacuole (animals)

Golgi

ER (SER and RER)

Vesicles (bubbles)

Organelles 

• Have specialized structures 

  • Special functions

• Containers

  • Different local environments

  • Separate cells into compartments

• Membranes as sites for chemical reactions

  • Unique combo of lipids and protein

Jobs of the Cell

1. Make Proteins - proteins control EVERY cell function 

2. Make Energy - for daily life; for repair

3. Make More Cells - growth, repair

Protein Assembly Line

Nucleus that has DNA ) - Ribosome - RER - Vesicle - Golgi - Vesicle - Cell Membrane

Nucleus Function

Protects DNA

Nucleus Structure

Note: allows large macromolecules to pass through

1. Nucleolus (creates ribosomes)

2. Nuclear Envelope / Membrane

3. Nuclear pore

The Messenger

• Instructions for a protein are copied from DNA by mRNA

• mRNA carries message to the cytoplasm through a nuclear pore

Ribosome Function

Protein Production

Ribosome Structure

rRNA and Protein

• two subunits combine (large and small)

Types of Ribosomes

• Free

  • In cytoplasm

  • Makes protein for cytoplasm

• Attached

  • Attached to ER

  • Makes proteins for export

Endoplasmic Reticulum (ER) Function

Passes proteins (RER)

Makes membranes (SER)

Endoplasmic Reticulum (ER) Structure

Membrane of ER is connected to the nuclear membrane

Types of ER: Smooth ER

• Membrane production

• Many metabolic processes - build or break

Types of ER: Smooth ER

Synthesis

Makes lipids (oils, steroids, phospholipids)

Types of ER: Smooth ER

Hydrolysis

Glycogen hydrolyzes into glucose

Detoxifies drugs - most in liver

Types of ER: Rough ER

Produce proteins for exporting out of cell

• Protein secreting cells

• Package into transport vesicles for export

REVIEW: Steps in making a protein

1. The DNA in the nucleus holds the instructions for a protein

2. mRNA in nucleus copies instructions

3. mRNA moves out of the nucleus through a nuclear pore

4. mRNA goes to a ribosome to make a protein

5. Ribosome and amino acids go in correct order

6. RER folds the protein

7. Travels through vesicle to Golgi

8. Golgi finishes the protein

9. Travels through vesicle to cell membrane

10. Leaves out cell membrane

Cells making energy overview

• Take in food and digest it

• Take in oxygen

• Make ATP

• Remove waste

What is ATP?

ENERGY

Lysosomes [only in animal cells] Function

Note: found in white blood cells

• Little stomach of the cell

  • Digests macromolecules

• Clean up crew

  • Cleans up broken down organelles

Lysosomes [only in animal cells] Structure

Vesicle of digestive enzymes

Lysosome Digestion: How it works

Lysosomes fuse with food vacuole

• polymer: digested into monomers then passed to cytoplasm to become nutrients

  • Works at pH 5

  • Cytosol (cytoplasm) has pH 7

  • Means: it will not break down in another pH

Lysosome Failure: When things go wrong

Digestive enzymes do not work on lysosome

Diseases of lysosomes are often fatal

Example: Krabbes diseases

Lysosome Failure: Steps

1. Picks up biomolecules but cannot digest one

2. Fills up with undigested material

3. Grow larger until disrupts cell and organ function

When cells need to die…

Apoptosis - Lysosomes can be used to kill cells when they are supposed to be destroyed

• Auto-destruct process

• Lysosomes break open and kill cells 

How do cells make energy?

Cells convert energy into forms they can use

Mitochondria (how it makes energy) - animals and plants

Food / Nutrients make a large amount of ATP

Chloroplast (how it makes energy) - plants

Sunlight makes a small amount of ATP

Transformed into food

Goes up to Mitochondria

Large amount of ATP produced 

ATP vs Glucose

ATP: active energy

Glucose: stored energy

Mitochondria AND Chloroplast BOTH…

• Have double membrane 

• Make ATP

• Have own DNA

• Move and divide 

Mitochondria Function

• Cellular respiration

• Generate ATP

Mitochondria Structure

Note: 2 membranes add to the surface area

ATP generated along Cristae

What cells have mitochondria?

Almost all EUKARYOTIC cells have mitochondria

• Either 1 very large mitochondrion or 100s to 1000s of individual mitochondria

• # of mitochondria is correlated with activity

• More activity = more energy needed = more mitochondria

Chloroplast Function

• Photosynthesis

• Make ATP

Chloroplast Structure

Note: they are GREEN

Vacuoles and Vesticles Function

Little transfer ships

• Think of Glinda the Good in a bubble, traveling around

Examples of Vacuoles

1. Food vacuole - animal

2. Contractile - protists

3. Central - plants

REVIEW: Steps in making energy

1. Food taken in through cell membrane into food vacuole

2. Food vacuole fuses with lysosome

3. Lysosome breaks food down into glucose

4. Glucose enters cytoplasm

5. Glucose taken in by mitochondria to make ATP

Cytoskeleton Function

• Structural Support (microtubules) - bones

  • Maintains shape of cell

  • Provides anchorage for organelles 

• Motility (microfilaments) - muscle

  • Cell locomotion ~ cilia and flagella are examples

• Regulation: organizes structures and activities of cell

Centrioles [animals only] Function

• Cell division

• Animals: pair of centrioles

• Organize cytoskeleton

• Guide chromosomes

REVIEW: Steps in making more cells

1. The cell copies its DNA and prepares for division

2. Centrioles organize the cytoskeleton and guide chromosomes

3. Centrioles move to opposite ends and form spindle fibers

4. Chromosomes line up in the middle of the cell

5. Spindle fibers pull sister chromatids apart

6. Microfilaments pinch the cell in two

7. Two identical cells are formed with the same DNA 

Plasma Membrane

• Very thin

• Fluid, fatty makeup

• Very flexible, yet stable

Phospholipid Bilayer Make-Up

• Lipids are hydrophobic

• Phosphates are hydrophylic

• Form 2 layers w/ the fatty acid tails in middle

• Phosphate heads point toward watery environment

Phospholipid Bilayer Traits

• Unsaturated, thus fluid-like

• The only things that can get through the fatty acids are other hydrophobic substances, or small molecules

Cholesterol 

• Lipid

• Patch the membrane, keeping some things from coming in

• Keep the membrane fluid

Glycocalyx 

• Carbohydrate chains that extend from the outside of cell

• Binding sites

• Lubricate cells

• Allow them to stick together

Glycocalyx Types

Glycoprotein - Protein

Glycolipid - Lipid

3 Types of Proteins

1. Integral: bound to the hydrophobic interior 

2. Peripheral: are not bound to the interior, attached to trans

3. Trans: all the way through

Proteins: Structure

• On the interior of the cell

• Attached to cytoskeleton of animal cells - anchor

Proteins: Recognition

Have binding sites whose shape can be recognized by immune cells

Proteins: Communication

• Cells can communicate w/ another over long distances by hormones

• Hormone is received by a receptor protein at a specific bonding site

• Hormone does not need to enter the cell - attach and leave a message

Proteins: Transportation

• Most materials cannot pass directly through cell membrane

• Proteins act as channels

• Materials move in and out of cell

Fluid Mosaic Model

Refer to picture!!! (Review)

Molecular Mvmt

Has random movement

• Molecules are in constant motion and spread out

Diffusion

Mvmt of molecules from a region of high concentration to a region of low concentration

• In diffusion, molecules move down a concentration gradient ALWAYS

Concentration Gradient

Difference between high and low

Semipermeable Membrane

Only let certain substances through it

Osmosis

The diffusion of water

Hypertonic Solution

Higher concentration of solutes outside the cell

• Water goes out

• Mass goes down

Hypotonic Solution

Lower concentration of solutes outside the cell

• Water goes in

• Mass goes up

Isotonic Solution

Solution inside cell and out have the same concentration

• Water goes in and out

• Mass stays the same

Molarity

How concentrated something is (Expressed with “M”)

Passive Transport - no energy

Simple Diffusion 

AND

Facilitated Diffusion

Simple Diffusion

• Does not require a protein channel

• Examples: Carbon Dioxide, Water

Facilitated Diffusion

• Aided by a transport protein

• Transport proteins are substance specific

• Examples: Glucose, Amino Acids

Compare and Contrast: Simple and Fascilitated Diffusion

BOTH move from high to low

HOWEVER simple goes through the phospholipid bilayer and facilitated moves through a protein. 

Active Transport - energy

• Sometimes cells need a higher or lower concentration of substance inside the cell than outside

  • Moving against concentration gradient

  • Substance specific

  • Requires energy (ATP)

Exocytosis

• Mvmt of large amounts of material OUT of a cell

  • Vesicle fuses to plasma membrane

  • Vesicle contents are released into the extracellular fluid

Endocytosis

Mvmt of materials INTO the cell

Endocytosis - Pinocytosis

“Cell drinking”

Endocytosis - Phagocytosis

“Cell eating”

Water Potential

Water Potential = Solutle Potential + Pressure Potential

• Water will flow from a high water potential to a low water potential