Chapter 6: Tour of the Cell

Question 1

1.Q: What are the three main components of the cell theory?

Answer 1

A: All living organisms are composed of cells, the cell is the basic unit of life, and all cells arise from pre-existing cells.

Question 2

2.Q: What are the main differences between prokaryotic and eukaryotic cells?

Answer 2

A: Prokaryotic cells are smaller, simpler, lack a nucleus, and have no membrane-bound organelles. Eukaryotic cells are larger, more complex, have a nucleus, and contain membrane-bound organelles.

Question 3

What are characteristics of all cells?

Answer 3

Have a plasma membrane
Contain genetic info
reproduce
carry out metabolic processes

Question 4

What are the similarities between prokaryotic and eukaryotic cells?

Answer 4

1. Both have a plasma membrane.
2. Both contain ribosomes (though they differ in size).
3. Both have DNA as their genetic material.
4. Both perform essential life processes.

Question 5

What is the structure and function of the nucleus?

Answer 5

Structure: Double membrane (nuclear envelope) with nuclear pores; contains chromatin (DNA).

Function: Stores genetic information; controls cell activities by regulating gene expression.

Question 6

What is the structure and function of ribosomes?

Answer 6

Structure: Composed of rRNA and proteins; can be free-floating or bound to rough ER.

Function: Site of protein synthesis.

Question 7

What is the structure and function of the endoplasmic reticulum?

Answer 7

Structure: Network of membranes; rough ER has ribosomes, smooth ER does not.

Function: Rough ER synthesizes proteins; smooth ER synthesizes lipids and detoxifies.

Question 8

What is the structure and function of the Golgi apparatus?

Answer 8

Structure: Stack of flattened membrane-bound sacs (cisternae).

Function: Modifies, sorts, and packages proteins and lipids for transport

Question 9

What is the structure and function of lysosomes?

Answer 9

Structure: Membrane-bound sacs filled with digestive enzymes.

Function: Breaks down waste materials and cellular debris.

Question 10

What is the structure and function of mitochondria?

Answer 10

Structure: Double membrane with inner folds (cristae).

Function: Site of cellular respiration; produces ATP.

Question 11

What is the structure and function of chloroplasts?

Answer 11

Structure: Contain thylakoids and stroma.
Function: Site of photosynthesis; converts light energy into chemical energy.

Question 12

What is the process for a secretory protein to exit a eukaryotic cell?

Answer 12

1. Protein synthesized by ribosomes on the rough ER.
2. Protein is folded and modified in the rough ER.
   3 Transported to the Golgi apparatus in vesicles.
3. Modified further in the Golgi and sorted.
4. Packaged into secretory vesicles that fuse with the plasma membrane to release the protein outside.

Question 13

How do you think a prokaryotic cell would secrete a protein?

Answer 13

Prokaryotic cells have ribosomes in the cytoplasm, and proteins are synthesized directly in the cytoplasm. They can then be transported across the cell membrane using specific transport mechanisms, as prokaryotes lack a Golgi apparatus.

Question 14

What happens if intermediate filaments are damaged?

Answer 14

Intermediate filaments provide structural support; damage can lead to cell shape distortion and compromised integrity.

Question 15

What happens if actin filaments are damaged?

Answer 15

Actin filaments are important for cell movement and division; damage can impair these processes and affect cell shape.

Question 16

What happens if microtubules are damaged?

Answer 16

Microtubules are crucial for cell division and intracellular transport; damage can lead to problems in cell division (mitosis) and the transport of organelles.

Question 17

What are the main types of cell junctions?

Answer 17

Tight Junctions: Prevent leakage between cells; important for creating barriers.

Gap Junctions: Allow for direct communication between adjacent cells; important for coordinated activity.

Desmosomes: Provide strong adhesion between cells; important for tissue integrity, especially in areas subject to stress (e.g., skin).