Exam 1 Study Guide Ch. 3

Question 1

What is the composition of the plasma membrane?

Answer 1

a phospholipid bilayer with embedded proteins arranged as a fluid mosaic. consists of lipids, proteins, and carbohydrates

Question 2

What are active transport processes?

Answer 2

Occur when a cell uses energy to move solutes across the membrane; move solutes “uphill” against the conc. gradient
-ex: sodium potassium pump

Question 3

What are passive transport processes?

Answer 3

move from high to low conc. w their gradient
-simple diffusion
-facilitated diffusion
-osmosis

Question 4

What is endocytosis?

Answer 4

vesicles bringing bulk materials into the cell
-phagocytosis
-pinocytosis
-receptor mediated endocytosis

Question 5

What is exocytosis?

Answer 5

vesicular transport processes that eject substances from cell; secretion

Question 6

What is the resting membrane potential? Is it active or passive?

Answer 6

produced by separation of oppositely charged particles across membrane in cells
-cells described as polarized
-passive

Question 7

What is the function of the mitochondria?

Answer 7

produces ATP for cellular energy

Question 8

What is the function of ribosomes?

Answer 8

site of protein synthesis

Question 9

What is the function of the endoplasmic reticulum?

Answer 9

Rough ER is used for storage and transport of proteins. Smooth ER is the site of steroid and lipid synthesis.

Question 10

What is the function of the Golgi apparatus?

Answer 10

packages proteins or other substances for export from cell or incorporation in plasma membrane

Question 11

What is the function of a lysosome?

Answer 11

to digest worn out cell organelles and foreign substances

Question 12

What is the function of a peroxisome?

Answer 12

contain oxidase enzyme that detoxify alcohol, free radicals, and other harmful chemicals

Question 13

Compare the functions of lysosomes and peroxisomes.

Answer 13

Lysosomes are responsible for the digestion of cells, while peroxisomes are responsible for the protection of cells against hydrogen peroxide.

Question 14

What are the cytoskeletal elements? What do they do?

Answer 14

Microfilaments: important in cell mobility, particularly in muscle cells
Intermediate Filaments: stable elements composed of a variety of proteins and resist mechanical forces acting on cell
Microtubules: form the internal structure of the centrioles and help determine cell shape

Question 15

What are the phases of the cell cycle?

Answer 15

1. Interphase
   -G1, S, G2
2. Prophase
3. Metaphase
4. Anaphase
5. Telophase
   Cytokinesis

Question 16

When is cell division complete?

Answer 16

Cytokineses

Question 17

What is a gene?

Answer 17

A sequence of DNA that encodes a protein

Question 18

What is the genetic code?

Answer 18

The rules by which the base sequence of a gene is translated into an amino acid sequence.

Question 19

What is translation?

Answer 19

the process in which genetic information carried by an mRNA molecule is decoded in the ribosome to form a particular polypeptide.

Question 20

What is transcription?

Answer 20

transfers information from a DNA base sequence to the complementary base sequence of an mRNA molecule.

Question 21

What are triplets?

Answer 21

Each sequence of three bases is called a triplet. The sequence of triplets in each gene forms a sentence that tells exactly how a particular polypeptide is meant to be. Ex: AAA

Question 22

What are codons?

Answer 22

The corresponding three base sequence on mRNA for each triplet.