The Cell

Question 1

Four Fundamental Tenets of the Cell Theory

Answer 1

All living things are composed of cells.
The cell is the basic functional unit of life.
Cells arise only from preexisting cells.
Cells carry genetic information in the form of deoxyribonucleic acid (DNA). This genetic material is passed on from parent to daughter cell.

Question 2

Are viruses considered living organisms?

Answer 2

No. They violate the third and fourth tenet of the Cell theory because virions can only by invading other organisms and because they may use ribonucleic acid (RNA) as their genetic information.

Question 3

Eukaryotes

Answer 3

Eukaryotic organisms can be unicellular or multicellular.

Have membrane-bound organelles and a nucleus

Question 4

Cell Membrane

Answer 4

The cell membrane and membranes of organelles contain phospholipid bilayers, which organize to form hydrophilic interior and exterior surfaces with hydrophobic core.

Question 5

Cytosol

Answer 5

Suspends the organelles and allows diffusion of molecules throughout the cell

Question 6

Nucleus

Answer 6

Contains DNA organized into chromosomes

Question 7

Nuclear membrane or envelop

Answer 7

It surrounds the nucleus and it consists of a double membrane that contains nuclear pores for two-way exchange of materials between the nucleus and cytosol

Question 8

Genes

Answer 8

Coding regions that organize DNA

Question 9

Nucleolus

Answer 9

Subsection of the nucleus in which ribosomal RNA (rRNA) is synthesized

Question 10

Mitochondria

Answer 10

Powerhouse of the cell.
Contains outer and inner membrane.
Can divide independently of the nucleus via binary fission
Can trigger apoptosis by releasing mitochondrial enzymes into the cytoplasm

Question 11

Outer membrane of the mitochondria

Answer 11

Forms a barrier with the cytosol

Question 12

Inner membrane of the mitochondria

Answer 12

Is folded into cristae and contains enzymes for the ETC

Question 13

Intermembrane space

Answer 13

Between the outer and inner membrane of the mitochondria

Question 14

Mitochondrial matrix

Answer 14

Located inside the innter mitochondrial membrane

Question 15

Lysosomes

Answer 15

Contain hydrolytic enzymes that can break down substances ingested by endocytosis and cellular waste products.
Can cause autolysis of the cells when these enzymes are released

Question 16

Endoplasmic Reticulum (ER)

Answer 16

A series of interconnected membranes and is continuous with the nuclear envelope

Question 17

Rough ER (RER)

Answer 17

Studded with ribosomes, which permit translation of proteins destined for secretion

Question 18

Smooth ER (SER)

Answer 18

Lipid synthesis and detoxification

Question 19

Golgi apparatus

Answer 19

Consists of stacked membrane-bound sacs in which cellular products can be modified, packaged, and directed to a specific cellular location

Question 20

Peroxisomes

Answer 20

Contains hydrogen peroxide and can break down very long chains of fatty acids via beta-oxidation.
They also participate in phospholipid synthesis and the pentose phosphate pathway

Question 21

Cytoskeleton

Answer 21

Provides stability and rigidity to the overall structure of the cell, while also providing transport pathways for molecules within the cell

Question 22

Microfilaments

Answer 22

Composed of actin
Microfilaments provide structural protection for the cell and can cause muscle contraction through interactions with mysoin
Help form cleavage furrow during cytokines in mitosis

Question 23

Microtubules

Answer 23

Composed of tubulin
They create pathways for motor proteins like kinesin and dynein to carry vesicles
They contribute to the structure of cilia and flagella, where they are organized into 9 pairs of microtubules in a ring with 2 microtubules at the center

Question 24

Centrioles

Answer 24

Found in the centrosomes and are involved in microtubules organization in the mitotic spindle

Question 25

intermediate filament

Answer 25

Involved in cell-cell adhesion and maintenance of the integrity of the cytoskeleton Help anchor organelles Examples: Keratin and desmin

Question 26

Epithelial tissues

Answer 26

Cover the body and line its cavities, protecting us against pathogen invasion and desiccation Some epithelial cells absorb or secrete substances or participate in sensation

Question 27

What is the functional part of the organ?

Answer 27

Epithelial cells form the parenchyma in most organs

Question 28

How are the epithelial cells polarized?

Answer 28

One side faces the lumen or the outside, and the other side faces blood vessels and structural cells

Question 29

Types of epithelial layers

Answer 29

Simple epithelia: has one layer Stratified epithelia: has many layers Pseudostratified epithelia: appear to have multiple layers due to differences in cell heights, but only have one layers

Question 30

Shapes of epithelial cells

Answer 30

Cuboidal cells: cube shaped Columnar cells: long and narrow Squamous cells: flat and scalelike

Question 31

Connective tissues

Answer 31

Suppor the body and provide a framework for epithelial cells

Question 32

Stroma

Answer 32

Connective tissues form the stroma or support structure by secreting materials to form an extracellular matrix

Question 33

Examples of connective tissues

Answer 33

Bone, cartilage, tendon, ligaments, adipose tissue, and blood