Chapter 4

Question 1

Be able to state and explain the cell theory.

Answer 1

theory all living things are composed of cells and all cells come from other cells.

Question 2

Describe the structure and function of the Cell (Plasma) membrane – (what macromolecules make up the plasma membrane and what is/are the function(s) of each.

Answer 2

The plasma membrane separates the living cell from its nonliving surroundings.
The plasma membrane and other membranes of the cell are composed mostly of phospholipids, which group together to form a two-layer sheet called a phospholipid bilayer.
2. Each phospholipid is composed of two distinct regions:
a. a “head” with a negatively charged phosphate group and
b. two nonpolar fatty acid “tails.”
3. Suspended in the phospholipid bilayer of most membranes are proteins that
a. help regulate traffic across the membrane and
b. perform other functions.

Question 3

Understand why the Plasma membrane is called a fluid mosaic model.

Answer 3

The plasma membrane is a fluid mosaic:

a. fluid because molecules can move freely past one another and
b. a mosaic because of the diversity of proteins in the membrane.

Question 4

plasma membrane

Answer 4

A selectively-permeable phospholipid bilayer forming the boundary of the cells. A FLUID MOSAIC because of diverse proteins and phospholipids that are mobile.

Question 5

cytoplasm

Answer 5

In eukaryotic cells, the cytoplasm is that part of the cell between the cell membrane and the nuclear envelope. It is the jelly-like substance in a cell that contains the cytosol, organelles, and inclusions, but not including the nucleus.

Question 6

cell wall

Answer 6

a rigid structure that surrounds the cell membrane and provides support to the cell, strong wall outside a plant cell’s plasma membrane that protects the cell and maintains its shape

Question 7

ribosomes

Answer 7

tiny structures that build proteins according to the instructions from the DNA

Question 8

cytoskeleton

Answer 8

A meshwork of fine fibers in the cytoplasm of a eukaryotic cell: includes microfilaments, intermediate filaments, and microtubules.

Question 9

mitochondrion

Answer 9

Use glucose to produce cellular energy, ATP. Found in both animal AND plant cells

Question 10

Rough ER

Answer 10

produces proteins- it is called rough because it is studded with ribosomes. These ribosomes produce membrane proteins and secretory proteins

Question 11

smooth ER

Answer 11

produces lipids such as steroids and other hormones. Helps liver cells detoxify circulating drugs. Smooth because it does not have ribosomes

Question 12

Golgi apparatus

Answer 12

works in partnership with the ER. Receives, refines, stores, and distributes chemical products of the cell.

Question 13

nucleus

Answer 13

a membrane-bound structure that houses most of a eukaryotic cell’s DNA

Question 14

centriole

Answer 14

a minute cylindrical organelle near the nucleus in animal cells, occurring in pairs and involved in the development of spindle fibers in cell division.

Question 15

lysosome

Answer 15

a membrane-bound sac of digestive enzymes found in animal cells. Its main function is to break down substances such as waste products or old organelle which are recycled and used to make new compounds.

Question 16

flagella

Answer 16

A long appendage that propels protists through the water and moves fluids across the surface of many tissue cells in animals.

Question 17

cilia

Answer 17

A short appendage that propels some protists through the water and moves fluids across the surface of many tissues in cells and animals.

Question 18

chloroplasts

Answer 18

Use energy produced by the sun to make glucose and cellular components

Question 19

central vacuole

Answer 19

is the largest organelle inside plant cells. a membrane bound sack that functions as a storage center and regulates the amount of water inside a cell

Question 20

leucoplasts

Answer 20

PLASTIDS that Are colorless and store starch. Found in roots

Question 21

transport vesicles

Answer 21

move molecules between locations inside the cell, e.g., proteins from the rough endoplasmic reticulum to the Golgi apparatus. Membrane-bound and secreted proteins are made on ribosomes found in the rough endoplasmic reticulum.

Question 22

chromosomes

Answer 22

cells have one or more carrying genes made of DNA

Question 23

nucleolus

Answer 23

dark spot in the nucleus where ribosomes are made

Question 24

Describe the Endomembrane system – Be able to trace the production of a protein to the secretion of a protein.

Answer 24

The endomembrane system in a cell consists of

a. the nuclear envelope,
b. the endoplasmic reticulum,
c. the Golgi apparatus,
d. lysosomes, and
e. vacuoles.
2. These membranous organelles are either
a. physically connected or
b. linked by vesicles, sacs made of membrane.

Question 25

Be able to compare/contrast eukaryotic vs. prokaryotic cells

Answer 25

Prokaryotic cells include
i. Bacteria and
ii. Archaea.
b. Eukaryotic cells include
i. protists,
ii. plants,
iii. fungi, and
iv. animals.
a. They are all bounded by a thin plasma membrane.
b. Inside all cells is a thick, jelly-like fluid called the cytosol, in which cellular components are suspended.
c. All cells have one or more chromosomes carrying genes made of DNA.
d. All cells have ribosomes, tiny structures that build proteins according to the instructions from the genes.
3. Prokaryotic cells are older than eukaryotic cells.
a. Prokaryotes appeared about 3.5 billion years ago.
b. Eukaryotes appeared about 2.1 billion years ago.
4. Prokaryotic cells are
a. usually smaller than eukaryotic cells and
b. simpler in structure.
5. Eukaryotes
a. Only eukaryotic cells have organelles, membrane-enclosed structures that perform specific functions.
b. The most important organelle is the nucleus, which
i. houses most of a eukaryotic cell’s DNA and
ii. is surrounded by a double membrane.
6. A prokaryotic cell lacks a nucleus.
a. Its DNA is coiled into a nucleus-like region called the nucleoid, which is not partitioned from the rest of the cell by membranes.
7. Figure 4.2 depicts
a. an idealized prokaryotic cell and
b. a micrograph of an actual bacterium.
8. Surrounding the plasma membrane of most prokaryotic cells is a rigid cell wall, which
a. protects the cell and
b. helps maintain its shape.
9. Prokaryotes can have
a. short projections called pili, which can also attach to surfaces, and/or
b. flagella, long projections that propel them through their liquid environment.
B. An Overview of Eukaryotic Cells
1. Eukaryotic cells are fundamentally similar.
2. The region between the nucleus and plasma membrane is the cytoplasm.
3. The cytoplasm of a eukaryotic cell consists of various organelles suspended in the liquid cytosol.
4. Most organelles are found in both animal and plant cells. But there are some important differences.

Question 26

Be able to compare/contrast plant cells vs. animal cells

Answer 26

Most organelles are found in both animal and plant cells. But there are some important differences.

a. Only plant cells have chloroplasts (where photosynthesis occurs).
b. Only animal cells have lysosomes (bubbles of digestive enzymes surrounded by membranes

Question 27

Organelles

Answer 27

membrane-enclosed structures that perform specific functions