Cell Theory and Eukaryotic Cells

Question 1

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

More recently:
- Cells carry genetic info via DNA: this is passed on from parent to daughter cell

Question 2

Nucleus

Answer 2

Contains all of the genetic material necessary for replication of the cell. Surrounded by the nuclear membrane or envelope

Question 3

Nuclear membrane or envelope

Answer 3

A double membrane that maintains a nuclear environment separate and distinct from the cytoplasm

Question 4

Nuclear pores

Answer 4

In the nuclear membrane; allow selective two-way exchange of material between the cytoplasm and the nucleus.

Question 5

Genes

Answer 5

Coding regions on genetic material (DNA)

Question 6

Nucleolus

Answer 6

Subsection of nucleus, where the ribosomal RNA (rRNA) is synthesized. Actually takes up approximately 25% of the volume of the entire nucleus; dark spot in nucleus.

Question 7

Mitochondria structure

Answer 7

Outer membrane: serves as barrier between cytosol and inner environment of mitochondrion.
Inner membrane, arranged in foldings called cristae, contain molecules and enzymes of electron transport chain..
Intermembrane space: space between inner and outer membranes
Matrix: Space inside the inner membrane

Question 8

Cytoplasmic/extranuclear inheritance and mitochondria

Answer 8

Mitochondria are semi-autonomous: the contain some of their own genes and replicate independently of the nucleus via binary fission.

Question 9

How are mitochondria thought to have originated

Answer 9

When the engulfing of an aerobic prokaryote by an anaerobic prokaryote resulted in a symbiotic relationship.

Question 10

Mitochondria’s roles in the cells

Answer 10

Can keep the cell alive by providing energy (ATP), and also can kill the cell by release of enzymes from electron transport chain –> kick-starts apoptosis, programmed cell death

Question 11

Lysosomes

Answer 11

Membrane-bound structures containing hydrolytic enzymes that are capable of breaking down many different substrates, including substances ingested by endocytosis and cellular waste products

Question 12

Endosomes

Answer 12

They transport, package, and sort cell material travelling to and from the membrane

Question 13

Where do endosomes transport materials to?

Answer 13

The trans-golgi, the cell membrane, or the lysosomal pathway for degradation

Question 14

Autolysis

Answer 14

Process that results when lysosomes release their hydrolytic enzymes: results in apoptosis by directly degrading cellular components.

Question 15

Endoplasmic reticulum

Answer 15

Series of interconnected membranes that are actually contiguous with the nuclear envelope. Includes smooth and rough ER

Question 16

Rough ER (RER)

Answer 16

Studded with ribosomes, which permit translation of proteins destined for secretion directly into its lumen

Question 17

Smooth ER (SER)

Answer 17

Lacks ribosomes and is utilized primarily for lipid synthesis (such as the phospholipids in the cell membrane) and the detoxification of certain drugs and poisons. It also transports proteins from the RER to the Golgi Apparatus

Question 18

Golgi Apparatus

Answer 18

Consists of stacked membrane-bound sacs; materials from ER are transferred to the Golgi apparatus in vesicles. Inside the Golgi Apparatus, cellular products are modified by adding signal sequences –> then repackaged into vesicles, which are directed to correct cellular location.

Question 19

Peroxisomes

Answer 19

Contain hydrogen peroxide; one of the primary functions is the breakdown of very long chain fatty acids via Beta-oxidation. They participate in the synthesis of phospholipids and contain some of the enzymes involved in the pentose phosphate pathway

Question 20

Cytoskeleton

Answer 20

Provides structure to the cell and helps it to maintain its shape. Also provides a conduit for the transport of materials around the cell

Question 21

3 components of cytoskeleton

Answer 21

Microfilaments, microtubules, and intermediate filaments

Question 22

Microfilaments

Answer 22

Made up of solid polymerized rods of actin. Actin filaments are organized into bundles and networks and are resistant to both compression and fracture, providing protection for the cell.

Question 23

Functions of microfilaments

Answer 23

Actin filaments can also use ATP to generate force for movement by interacting with myosin, such as in muscle contraction.
Microfilaments also play a role in cytokinesis, or the division of materials between daughter cells.
During mitosis, the cleavage furrow is formed from microfilaments.

Question 24

Microtubules

Answer 24

Hollow polymers of tubulin proteins. They radiate throughout the cell, providing the primary pathways along which motor proteins like kinesin and dynein carry vesicles. They make up cilia and flagella

Question 25

Cilia

Answer 25

Projections from a cell that are primarily involved in the movement of materials along the surface of the cell

Question 26

Flagella

Answer 26

Structures involved in the movement of the cell tiself, such as the movement of sperm cells through the reproductive tract

Question 27

CIlia and flagella share the same structure –> what is it?

Answer 27

Composed of 9 pairs of microtubules forming an outer ring, with 2 microtubules in the center. Known as 9+2 strucutre, seen only in eukaryotic organelles of motility

Question 28

Centrioles

Answer 28

Found in a region of the cell called the centrosome. They are the organizing centers for microtubules and are structured as 9 triplets of microtubules with a hollow center

Question 29

What do centrioles do during mitosis

Answer 29

The centrioles migrate to opposite poles of the dividing cell and organize the mitotic spindle. The microtubules emanating from the centrioles attach to the chromosomes via complexes called kinetochores and exert force on the sister chromatids, pulling them apart.

Question 30

Intermediate filaments

Answer 30

Diverse group of filamentous proteins, which includes keratin, desmin, vimentin, and lamins. Many intermediate filaments are involved in cell-cell adhesion or maintenance of overall integrity of the cytoskeleton. They help anchor other organelles, including nucleus –> also are able to withstand tremendous amount of tension.

Question 31

The 4 tissue types

Answer 31

Epithelial, connective, muscle, and nervous tissue

Question 32

Epithelial tissues

Answer 32

Cover the body and line its cavities, providing a means for protection against pathogen invasion and dessication.

Question 33

Basement membrane

Answer 33

An underlying layer of connective tissue to which epithelial cells are tightly joined to (and each other).

Question 34

Parenchyma

Answer 34

The functional parts of the organ: in most organs, epithelial cells constitute the parenchyma.

Question 35

Characteristics of epithelial cells

Answer 35

They are often polarized, with one side facing a lumen or the outside world, and the other side interacting with underlying blood vessels and structural cells.

Question 36

Simple epithelia

Answer 36

Have one layer of cells

Question 37

Stratified epithlia

Answer 37

Have multiple layers

Question 38

Pseudostratified epithelia

Answer 38

Appear to have multiple layers due to differences in cell height but are, in reality, only one layer

Question 39

Cuboidal cells

Answer 39

cube-shaped

Question 40

Columnar cells

Answer 40

Long and thin

Question 41

Squamous cells

Answer 41

Flat and scale-like

Question 42

Connective Tissue

Answer 42

Supports the body and provides a framework for the epithelial cells to carry out their functions.

Question 43

Stroma

Answer 43

The support structure of the body which the connective tissue is the main contributor to

Question 44

Examples of connective tissues

Answer 44

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

Question 45

Extracellular matrix

Answer 45

Materials such as collagen and elastin which most cells in connective tissues produce and secrete