Organelles and the Cell Membrane

Question 1

Nucleus

Answer 1

contains DNA

Question 2

Nucleolus

Answer 2

inside nucleus and creates subunits of ribosomes assembled from protein and RNA

Question 3

Ribosomes

Answer 3

Ribosomes use the information from RNA to combine amino acids and form proteins

Question 4

Mitochondria

Answer 4

mitochondria is the powerhouse of the cell and creates energy for the cell

Question 5

Chloroplasts

Answer 5

convert the sun’s light into energy.

in plants only

Question 6

Why is the cell membrane based on the Fluid Mosaic Model?

Answer 6

The Fluid Mosaic Model explains the cell membrane because it’s made of many small parts, like proteins and lipids, that can move around. These parts work together like a mosaic, making the membrane flexible and allowing it to do different jobs.

Question 7

Why is the cell membrane asymmetrical?

Answer 7

The cell membrane is asymmetrical because its components, like proteins, cholesterol, and phospholipids, are arranged differently on each side. This uneven distribution allows them to carry out their specific functions in the best possible way.

Question 8

Glycolipid

Answer 8

membrane lipid bound to a carbohydrate

Question 9

Glycoprotein

Answer 9

membrane component that contains a sugar and is bound to amino acid

Question 10

What are the main molecules forming the structure of the cell membrane?

Answer 10

Glycoprotein, Glycolipids, phospholipids, integral proteins

Question 11

What molecules are embedded in the membrane?

Answer 11

Cholesterol, integral proteins

Question 12

What influences fluidity of a cell membrane (i.e., discuss the role of cholesterol at high/low temperatures)

Answer 12

The fluidity of a cell membrane is affected by:

• Temperature: High temperatures make it more fluid, low temperatures make it stiffer.
• Lipid type: Unsaturated fats make it more fluid, while saturated fats make it stiffer.
• Cholesterol: At high temperatures, cholesterol keeps the membrane from becoming too fluid, and at low temperatures, it stops it from becoming too rigid.

Question 13

What is the difference between: integral, peripheral, and transmembrane proteins?

Answer 13

• Integral proteins: Embedded in the membrane.
• Transmembrane proteins: A type of integral protein that goes across the entire membrane.
• Peripheral proteins: Attached to the surface of the membrane.

Question 14

What are the four functional categories of membrane proteins? Give an example for each.

Answer 14

1. Transport proteins: Help move substances across the membrane (e.g., Hemoglobin).
2. Enzyme activity: Some proteins act as enzymes in processes like photosynthesis or cellular respiration (e.g., Amylase).
3. Triggering signals: Bind to chemicals like hormones, changing cell activity (e.g., Insulin receptor).
4. Attachment and recognition: Connect to the cytoskeleton or help in cell recognition (e.g., Integrins).