Bsci170 Exam 2

Question 1

Four different ways to manipulate the carbon backbones of organic molecules to make a diversity of different molecules?

Answer 1

1. Cells can change length of carbon backbone. (adding or removing carbons)
2. Cells can change the shape of the carbon backbone by adding branches. (isomers)
3. Cells can add double or triple bonds between carbons in the backbone
4. Cells can make the carbon backbone into a ring structure.

Question 2

What are the effects of different functional side groups on organic molecules.

Answer 2

1. Hydroxyl groups to add polarity to organic molecules
2. Carbonyl groups to change how molecules are used in certain chemical reactions.
3. Carboxyl groups to add negative charge to molecules in water.
4. Amino groups add positive charge to molecules in water.
5. Sulfhydryl groups to create covalent bonds between different molecules or different parts of large proteins.
6. Phosphate groups add energy to molecules making them less table and more chemically reactive
7. Methyl groups to temporarily change the identity of molecules to regulate their function.

Question 3

Recognize and illustrate the 7 functional side groups.

Answer 3

1. Hydroxyl group (OH)
2. Carbonyl group (=O)
3. Carboxyl group (COOH)
4. Amino group (NH3)
5. Sulfhydryl group (SH)
6. Phosphate group (PO4)
7. Methyl group (CH3)

Question 4

When should reactions use dehydration synthesis?

Answer 4

Dehydration synthesis should be used to eliminate or reduce the amount of water molecules. Or when macromolecules are assembling.

Question 5

When should hydrolysis be used?

Answer 5

Hydrolysis should be used to break down polymers into monomers. Or when macromolecules are being dissembled.

Question 6

What groups add polarity to molecules to make them more hydrophilic?

Answer 6

Hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl

Question 7

Compare the structure of triglycerides and phospholipids.

Answer 7

Triglycerides consist of 3 fatty acids attached to a glycerol molecule. Phospholipids have a glycerol with two VERY hydrophobic fatty acid tails and one VERY hydrophilic head.

Question 8

Contrast structural changed in saturated and unsaturated fatty acids

Answer 8

Saturated fatty acids lack double bonds and forms straight molecules that can pack closely together so they are solid at room temp (fats). Unsaturated fatty acids have one or more double bonds and are bent so they push each other further apart making them fluid (oil).

Question 9

What is amphipathic?

Answer 9

The balance between non-polar and polar regions.

Question 10

What is an important membrane structure function for steroid

Answer 10

An important membrane structure-function relationship is cholesterol.

Question 11

What are proteins?

Answer 11

Proteins are large polymers made by connection amino acids along with peptide bonds to make polypeptides.

Question 12

What factors influence protein structure at different levels of organization?

Answer 12

1. Primary structure is the sequence of amino acids. There are 20 naturally occurring amino acids each with a different R-group. This gives them different properties such as hydrophilic, hydrophobic, charged, polar, acidic, or basic.
2. Secondary structure is a consequence of hydrogen bonding between the hydroxyl and amino groups along the polypeptide backbone. This can fold short sections of the polypeptide into beta pleated sheets or coil them into alpha helices.
3. Tertiary structure is a consequence of interactions between R-groups that bring helices and pleated sheets together, folding a single polypeptide into a complex three dimensional shape.
4. Quaternary structure is the consequence of interactions between R-groups. This creates a single protein made of multiple polypeptides.

Question 13

What are the different types of membrane proteins?

Answer 13

Integral membrane proteins, peripheral proteins, lipid-anchored proteins.

Question 14

What are the different transport proteins?

Answer 14

Transport proteins, receptors, junction proteins, and cell recognition proteins.

Question 15

Describe the types of membrane proteins.

Answer 15

Integral membrane proteins insert into the hydrophobic region of the hydrophilic peripheral proteins which associate with either side of the membrane at the lipid head. Lipid-anchored proteins are hydrophilic but attach to the membrane using a fatty acid. molecule that inserts into the hydrophobic layer.

Question 16

What is the fluid mosaic model?

Answer 16

This emphasizes that most of the phospholipids and many proteins in the membrane are not covalently lined to other molecules and are free to move around the membrane.

Question 17

Describe how facilitated diffusion is accomplish for different types of solutes across a selectively permeable membrane?

Answer 17

Transport proteins make cell membranes selectively permeable and allow for the facilitated diffusion of polar molecules and ions across the membrane.

Question 18

Examples of active transport using direct or indirect energy.

Answer 18

Transport proteins that move a single solute across the membrane are called uniport proteins/ Co-transport proteins can move more than one solute at a time (COUPLED TRANSPORT), either in the same direction (SYMPORT) or in opposite directions (ANTIPORT).

Question 19

What proteins work together in co-transport problems?

Answer 19

Uniport proteins, coupled transport, symport, and anti port.

Question 20

Define different types of bulk transport

Answer 20

1. Bulk transport
   - can move many molecules at a time using the membrane itself in the process.
2. Endocytosis
   - brings assemblages of molecules into a cell and can involve different processes.
3. Phagocytosis
   - creates large vesicles and can bring in large amounts of material
4. Pinocytosis
   - creates small vesicles that are used to transport water
5. Receptor mediated endocytosis
   - uses transmembrane receptor proteins to selectively bring in large amounts of the same solute beer specifically.

Question 21

What happens during ligand binding of receptors?

Answer 21

Ligand binds to a receptor protein causing a change in the shape of the protein.

Question 22

What are some advantages signal transduction cascades provide?

Answer 22

The signal transduction occurs when proteins inside the cell recognize the change in shape of a receptor bound by ligand and trigger a signal transduction cascade. This determines if what proteins are in the signal transduction cascade to ensure appropriate response to a signal.

Question 23

What are the key features of gated ion channels?

Answer 23

Gated ion channels are normally closed but will open and allow facilitated diffusion when found by a signaling molecule.

Question 24

What are key features of cytoplasmic receptors?

Answer 24

Cytoplasmic receptors bind hydrophobic ligands such as the steroid hormones, which can freely pass through the membrane.

Question 25

Key features of Receptor tyrosine kinases

Answer 25

Transmembrane receptors that have the ligand binding part outside the cell and an enzyme part inside the cell on a single protein.

Question 26

Key features of G-protein coupled receptors

Answer 26

Transmembrane receptors that have separate proteins for ligand binding and enzymatic response.