Day 6 January 31st

Last time –Macromolecules – carbs, lipids,

proteins, nucleic acidsBasics of cells

THE EXAM

How did you feel about the exam?

1. I was ready, and I did well2. I was ready, but I didn’t do well3. I wasn’t sure I was ready, but I feel I did well4. I wasn’t ready, and I bombed!5. IDK???

I’m so sick today

• Sorry I’m not there today, but I’m sick as a dog. Ear hurts, throat hurts, and rather than spread illness, I’m going to stay home today.

• Please read through the slides, and reference them in the book. You should read Chapter 3 THOROUGHLY. It was the weakest part of the exam.

Humans, deep down, may be part bacteria.

How can that be?

3-4. All cells are bordered by plasma membranes.

Why are plasma membranes such complex structures?

They perform several critical functions.

Food and nutrients inWater inWaste outExport moleculesAbsorb or release heat

3.5 Molecules embedded within the plasma membrane help it perform its functions.

What determines whether a protein resides on the surface or extends through the bilayer?

There are four primary types of membrane proteins, each of which performs a different function.

Lipids that make up the cell membrane are hydrophobic. Hydrophilic molecules, like glucose, cannot cross this barrier. What major component of the plasma membrane helps glucose get into and out of the cell?1. Phospholipids2. Carbohydrates3. Nucleic acids4. Proteins5. Fatty acids

Lipids that make up the cell membrane are hydrophobic. Hydrophilic molecules, like glucose, cannot cross this barrier. What major component of the plasma membrane helps glucose get into and out of the cell?1. Phospholipids2. Carbohydrates3. Nucleic acids4. Proteins5. Fatty acids

The Plasma Membrane “Fluid Mosaic”

In addition to proteins, two other molecules are found in the plasma membrane:

1. Short, branched carbohydrate chains 2. Cholesterol – lipid (keeps it flexible)

Smallmouth Bass and Yellow Perch are considered warm water fish, whereas certain species of char are found in the arctic. Which fish do you think might have the most cholesterol in the membranes of its cells?

1. Smallmouth Bass2. Yellow Perch3. Arctic char4. Both 1 and 2 are

correct.

Smallmouth Bass and Yellow Perch are considered warm water fish, whereas certain species of char are found in the arctic. Which fish do you think might have the most cholesterol in the membranes of its cells?

1. Smallmouth Bass2. Yellow Perch3. Arctic char4. Both 1 and 2 are

correct.

3.6 Faulty membranes can cause disease.

Cystic Fibrosis

3.7 Membrane surfaces have a “fingerprint” that identifies the cell.

Cells with an improper fingerprint are recognized as foreign and are attacked by your body’s defenses.

Why is it extremely unlikely that a person will

catch HIV from casual contact—

such as shaking hands—with an infected

individual?

Which of the cell membrane functions below is possible due to the presence of proteins in the plasma membrane?

1. The cell membrane determines what molecules will enter or leave the cell.

2. The cell membrane contains proteins that can bind to messages sent from other cells and relay the message to the interior of the cell.

3. The cell membrane contains proteins that act as a fingerprint for distinguishing between self and foreign cells.

4. Both 1 and 2 are correct.5. All of the above.

Which of the cell membrane functions below is possible due to the presence of proteins in the plasma membrane?

1. The cell membrane determines what molecules will enter or leave the cell.

2. The cell membrane contains proteins that can bind to messages sent from other cells and relay the message to the interior of the cell.

3. The cell membrane contains proteins that act as a fingerprint for distinguishing between self and foreign cells.

4. Both 1 and 2 are correct.5. All of the above.

Diffusion and Concentration Gradients

• Solutes

• Solvents

How do laxatives relieve constipation?

Milk of magnesia and magnesium salts

Water moves via osmosis from the cells into the intestines.

An amoeba (a single-celled protist) is placed in a solution. The volume of the cell increases (cell swells). Which statement below is the correct interpretation of this result?1. The amoeba is in a hypertonic

solution.2. Water is moving into the

amoeba.3. The amoeba is in a isotonic

solution.4. Water is moving out of the

amoeba.

An amoeba (a single-celled protist) is placed in a solution. The volume of the cell increases (cell swells). Which statement below is the correct interpretation of this result?1. The amoeba is in a hypertonic

solution.2. Water is moving into the

amoeba.3. The amoeba is in a isotonic

solution.4. Water is moving out of the

amoeba.

Three types of endocytosis:

1. Phagocytosis

2. Pinocytosis

3. Receptor-mediated endocytosis

How can a lack of communication between cells lead to cancer?

Contact inhibition

Tumors

Plasmodesmata

Tube-like channels connecting the cells to each other and enabling communication and transport between them

Consider a plant as one big cell?

3.14 Cytoplasm and cytoskeleton: the cell’s internal environment, physical support, and movement.

Cytoskeleton: Three Chief Purposes

Endosymbiosis

Mitochondria may have existed as separate single-celled, bacteria-like organisms billions of years ago.

Mitochondria have their own DNA!

We all have more DNA from one parent than

the other.

Who is the bigger contributor: mom or dad?

Why?

Lysosomesround, membrane-enclosed, acid-filled

vesicles that function as garbage disposals

Which cellular component would be responsible for the classic shape of a red blood cell?

1. Nucleus2. Cytoskeleton3. Lysosome4. Mitochondria

Which cellular component would be responsible for the classic shape of a red blood cell?

1. Nucleus2. Cytoskeleton3. Lysosome4. Mitochondria

Rough Endoplasmic Reticulum

The Smooth Endoplasmic Reticulum

Which cells below would have the smoothest endoplasmic reticulum?

1. Kidney cells2. Kidney cells of an

alcoholic3. Liver cells4. Liver cells of an

alcoholic

Which cells below would have the smoothest endoplasmic reticulum?

1. Kidney cells2. Kidney cells of an

alcoholic3. Liver cells4. Liver cells of an

alcoholic

How can long-term use of one drug increase your resistance to another, different drug that you have never encountered?

3.18 Golgi apparatus: Where the cell processes products for delivery throughout the body

3.19 The cell wall provides additional protection and support for plant cells

3.20 Vacuoles: multipurpose storage sacs for cells

3.21 Chloroplasts: the plant cell’s power plant

Which answer below is not found in a eukaryotic cell?

1. Cell wall2. DNA without membrane3. Endoplasmic reticulum4. Chloroplast5. Lysosome

Which answer below is not found in a eukaryotic cell?

1. Cell wall2. DNA without membrane3. Endoplasmic reticulum4. Chloroplast5. Lysosome