Ch 6 - Pt 2 - Tour of the Cell

Question 0

What 3 compartments compose the chloroplast?

Answer 0

1) Intermembrane space
2) Stroma
3) Thykaloid

Question 1

Chloroplasts

Answer 1

1) Possess membrane system dividing the chloroplast into 3 compartments
2) Contains the green pigment chlorophyll that absorbs solar energy for use in synthesizing sugars
3) Self-replicating and contains own genetic material independent of the cell as a whole

Question 2

Mitochondria

Answer 2

1) Cell’s “powerhouse” with chemical reactions occurring on the surface of the inner membrane producing energy carrying molecules (ATP)
2) Self-replicating and contains own genetic material independent of the cell as a whole

Question 3

Endosymbiosis

Answer 3

One organism living inside another

Question 4

Endosymbiosis theory

Answer 4

States that some organelles such as mitochondria are derived from once free-living bacteria that colonized the cytoplasm of other single-celled organisms either through ingestion or parasitism

Question 5

How do mitochondria and chloroplasts (in plant cells) differ from the cells in which they occur?

Answer 5

Mitochondria and chloroplasts (in plant cells) have their own genomes with DNA sequences closer to those of bacteria than to those in the nuclear DNA of the cells in which they occur.

Question 6

Who first presented endosymbiotic theory?

Answer 6

Lynn Margulis presented endosymbiotic theory in the paper “On the origin of mitosing cells” in 1967

Question 7

Perixisomes

Answer 7

Compartments containing enzymes that break down toxins by removing H atoms and transferring them to O to produced hydrogen peroxide (H2O2)

Question 8

Cytosol

Answer 8

The jelly-like substance in which the organelles of the cytoplasm are suspended

Question 9

Cytoskeleton

Answer 9

The fibrous network that spans the cytosine to support the membranes and organelles of the cell. Includes actin, intermediate filaments, and microtubules.

Question 10

Properties of microfilaments (actin filaments)

Answer 10

1) Structure of 2 intertwined strands of actin
2) Diameter of 7 nm
3) Actin protein subunits
4) Functions mainly to maintain cell shape, manages changes in cell shape, muscle contraction, cytoplasmic streaming, cell motility, and cell division

Question 11

What is the arrangement of actin good for?

Answer 11

Actin is arrangers to bear pulling force (tension).

Ex: In muscle cells, actin is pulled upon by filaments comprised of the motor protein myosin

Question 12

Amoeboid movement

Answer 12

Movement of the cell that is achieved by the action of actin microfilaments that extend a pseudo podium outward from the surface of the cell.

(Ex: Cytoplasmic steaming moves the mass of the cell in the direction of the pseudopodium)

Question 13

Properties of intermediate filaments

Answer 13

1) Structure of fibrous proteins supercoiled into thicker cables
2) Diameter if 8-12nm
3) One of several different proteins of the keratin family serves as protein subunit
4) Functions mainly to maintain cell shape, anchorage of nucleus and certain other organelles, and formation of nuclear lamina

Question 14

Properties of microtubules (tubulin polymers)

Answer 14

1) Hollow tube structure; wall consists of 13 columns of tubulin molecules
2) Diameter of 25nm with 15nm lumen
3) Tubulin protein subunits
4) Functions mainly to maintain cell shape, cell motility, chromosome movements in cell division, and organelle movement

Question 15

Flagella and cilia

Answer 15

External appendages used for cell locomotion; contain dynein that acts against the microtubule structure to produce movement

Question 16

How does the arrangement of microtubules effect flagella and cilia?

Answer 16

The arrangements of microtubules are responsible for the beating of flagella and cilia

Question 17

Microvilli

Answer 17

Finger-like projections of the plasma membrane supported by bundles of actin. Increases the area of absorptive and digestive surfaces.

Question 18

3 types if cell junctions

Answer 18

1) Tight junctions
2) Desmosomes
3) Gap junctions

Question 19

Tight junctions

Answer 19

Proteins across membranes bind cells closely together, preventing molecules from passing between.

(Ex: intestinal cells)

Question 20

Desmosomes

Answer 20

“Spot welds” between cells formed from proteins and bundles of intermediate filaments that increases the strength of tissues.

(Ex: skin cells)

Question 21

Gap junctions

Answer 21

Tiny canals between cells through which cytoplasm and small molecules can pass.

(Ex: in nerve and muscle cells)

Question 22

Extracellular matrix

Answer 22

Surrounding animal cells; comprised of glycoprotein (proteins bonded by carbohydrates) including collagen

Question 23

Functions of the extracellular matrix

Answer 23

1) Support
2) Adhesion
3) Movement
4) Regulation

Question 24

Cell wall

Answer 24

The extracellular structure in plant cells that protects and supports the cell and helps maintain water balance

Question 25

Plasmodesmata

Answer 25

Channels that perforate the nonliving cell walls of plant and connect the cytoplasm of cells.