BMS 108 Ch. 3 Cell Structure

Question 0

What is another name for the plasma cell membrane?

Answer 0

Phospholipid bilayer

Question 1

What are the three main components of cells?

Answer 1

Plasma membrane, cytoplasm and nucleus

Question 2

What molecules are restricted from passing through the plasma cell membrane?

Answer 2

Polar, large, ions, most amino acids, proteins and glucose

Question 3

What gets through the plasma cell membrane?

Answer 3

nonpolar, small, lipids, steroids, gases and *H2O

Question 4

What is the fluid mosaic model of the plasma cell membrane?

Answer 4

The phospholipid bilayer is a sea with a constantly changing mosaic pattern.

Question 5

What functions do proteins in the plasma membrane serve?

Answer 5

structural support, transport of molecules across the membrane, and enzymatic control of chemical reactions at the cell surface.

Question 6

What is bulk transport?

Answer 6

a way cells move large molecules and particles across the plasma membrane.

Question 7

What is phagocytosis?

Answer 7

one way for a cell to take in particulate matter

Question 8

What is endocytosis?

Answer 8

another way to take large compounds into a cell; a way to make vesicles

*the membrane invaginates to take in a vesicle of extracellular substance

Question 9

What is Pinocytosis?

Answer 9

A non-specific endocytosis

Question 10

What is a specific endocytosis called?

Answer 10

Receptor Mediated Endocytosis

Question 11

Cells use _______ to export products into the extracellular fluid by bulk transport via secretory vesicles.

Answer 11

Exocytosis

Question 12

What is cilia?

Answer 12

moving projections from the cell that help move fluids over the plasma cell membrane

Question 13

What is a flagella?

Answer 13

a projection from the cell that propels the cell (human sperm)

Question 14

What is the function of microvilli?

Answer 14

To increase rate of absorption by increasing cell surface area.

Question 15

What is cytoplasm?

Answer 15

The jellylike matrix within a cell consisting of cytosol and organelles.

Question 16

What is the cytoskeleton?

Answer 16

A latticework of microfilaments and microtubules filing cytoplasm.

Question 17

What is transcription?

Answer 17

DNA -> RNA (same language)

Question 18

What is translation?

Answer 18

RNA -> protein (different language)

Question 19

What is a codon?

Answer 19

A three letter sequence of mRNA that are blueprints for a specific amino acid.

Question 20

Describe the steps in protein synthesis.

Answer 20

1. DNA pairs with complimentary RNA to form mRNA
2. Ribosomes read mRNA codons (triplets) which specifies an amino acid
3. Amino acids are linked together with peptide bonds in a sequence that forms a polypeptide chain.

Question 21

How does a ribosome form a polypeptide chain?

Answer 21

1. tRNA finds the proper codon for the amino acid it is carrying
2. Amino acids on adjacent tRNAs are brought together and linked enzymatically by peptide bonds
3. This forms a polypeptide; at a stop codon, it detaches from the ribosome.

Question 22

What does it mean that DNA Replication is “semiconservative”?

Answer 22

When DNA is unzipped, one half is replace by new nucleotides. Thus, the new DNA is 1/2 new and 1/2 old.

Question 23

What phase does a cell spend most of its life in?

Answer 23

Interphase

Question 24

What is mitosis?

Answer 24

Exact cell replication

Question 25

What are the four phases of mitosis?

Answer 25

1. prophase
2. metaphase
3. anaphase
4. telophase

Question 26

What are chromatids?

Answer 26

Duplicate strands of chromosomes connected by a centromere

Question 27

What is the purpose of mieosis?

Answer 27

To reduce genetic material by half (sex cells)

Question 28

How many phases are in mieosis?

Answer 28

2

Question 29

Does the reduction of genetic material happen in Meiosis I or II?

Answer 29

Meiosis I

Question 30

Why is meiosis called a reduction division?

Answer 30

because genetic material is reduced from 46 chromosomes to 23.

Question 31

What are two ways which cell death occurs?

Answer 31

Necrosis and Apoptosis

Question 32

What is necrosis?

Answer 32

Occurs when pathological changes kill a cell

Question 33

What is apoptosis?

Answer 33

Occurs as a normal physiological response; aka programmed cell death; involves lyosomes

Question 34

Describe the functions of Lysosomes.

Answer 34

“digestive system of cells”

• are single-membrane vesicle-like organelles containing digestive enzymes (>60), acidic
• involved in recycling cell components
• involved in apoptosis

Question 35

Describe the functions of Peroxisomes.

Answer 35

Vesicle-like organelles containing oxidative enzymes (oxidation = electron loss)
- involved in detoxification in liver (alcohol oxidation)

Question 36

Describe the functions of Mitochondria.

Answer 36

An energy producing organelle (ATP)

- in all cells except red blood cells, more where needed

Question 37

Describe the functions of Endoplasmic Reticulum.

Answer 37

A system of membranes specialized for synthesis or degradation of molecules.

• Rough ER contains ribosomes for protein synthesis
• Smooth ER contains enzymes for steroid synthesis and inactivation; also involved in Calcium storage

Question 38

Describe the functions of Ribosomes.

Answer 38

On the surface of Rough ER and free floating; necessary for translation

Question 39

Describe the functions of the Golgi Apparatus.

Answer 39

A stack of flattened sacks

• protein filled vesicles enter from the ER, contents are modified, sorted and leave the other side.
• lysosomes and secretory vesicles are formed in the Golgi Apparatus

Question 40

Describe the functions of Centrosomes.

Answer 40

Centrosomes, centrioles, and spindle fibers are involved in separating chromosomes during cell division (mitosis)

Question 41

Describe the functions of the nucleus.

Answer 41

• contains cell DNA (chromosomes)
• where DNA replication and RNA synthesis take place
• enclosed by a double membrane nuclear envelope (outer membrane is continuous with ER)