The Cell

Question 1

Four tenets of cell theory

Answer 1

(1) All living things are composed of cells
(2) The cell is the basic functional unit of life
(3) Cells arise only from preexisting cells
(4) Cells carry genetic information in the form of DNA which is passed on from parent to daughter cell

Question 2

Eukaryotic vs Prokaryotic Cells

Answer 2

Eukaryotic cells contain a true nucleus enclosed in a membrane while prokaryotic cells have no nucleus
Eukaryotic cells also have mitochondria or chloroplasts and have chromosomal DNA

Question 3

Nuclear pores

Answer 3

Found in the nuclear membrane; allows selective two-way exchange of material between the cytoplasm and the nucleus

Question 4

Nucleolus

Answer 4

a section of the nucleus; takes up about 25% of the nucleus; the location of ribosomal RNA (rRNA) synthesis

Question 5

Organization of DNA

Answer 5

Linear DNA is wound around organizing proteins known as histones and then further wound into strands called chromosomes

Question 6

Structure of the Mitochondria

Answer 6

Outer membrane - barrier between teh cytosol and inner environment
Inner membrane - arranged into folds called cristae
Cristae - location of enzymes and molecules of the ETC
Inter-membrane space - space between inner and outer membrane
Matrix - space inside the inner membrane

Question 7

Membrane-Bound Organelles

Answer 7

In eukaryotic cells, most organelles are membrane bound. This facilitates the compartmentalization of functions (i.e. separation of transcription and translation)

Question 8

The Nucleus

Answer 8

The control center of the cell; contains all the genetic material needed for replication; surrounded by the nuclear membrane or envelope (double membrane)

Question 9

Theory of the origin of mitochondria

Answer 9

Mitochondria are thought to have originated when teh engulfing of an aerobic prokaryote by an anaerobic prokaryote resulted in a symbiotic relationship

Question 10

Apoptosis

Answer 10

Programmed cell death; caused by release of enzymes from the ETC (found in the mitochondria)

Question 11

Lysosomes

Answer 11

Membrane-bound organelle containing hydrolytic enzymes to break things down.

Question 12

Endosomes

Answer 12

Transport, package and sort cell material travelling to and from the membrane (moves material to the trans-golgi, cell membrane, or lysosomal pathway for degradation)

Question 13

Autolysis

Answer 13

Release of lysosomal hydrolytic enzymes leads the the degradation of the cell

Question 14

Endoplasmic Reticulum

Answer 14

A series of interconnected membranes that are contiguous with the nuclear envelope. The double membrane is folded into a complex structure with a central lumen.

Rough ER - has ribosomes to allow for protein synthesis
Smooth ER - no ribosomes; lipid synthesis, detoxification of certain toxins, transports proteins from RER to Golgi apparatus

Question 15

Golgi Apparatus

Answer 15

Consists of stacked membrane bound sacs; materials come from RER in vesicles. The golgi apparatus modifies material by adding carbohydrates, phosphates, sulfates, and/or signal sequences to direct the delivery of modified material. Materials are repackaged into vesicles and sent to the correct location

Question 16

Peroxisomes

Answer 16

contains hydrogen peroxide; functions: breakdown of long fatty acids via beta-oxidation, participates in synthesis of phospholipids, and contain some enzymes involved in the pentose phosphate pathway

Question 17

Cytoskeleton

Answer 17

Provides structure and a conduit for transport of materials. Three components are microfilaments, microtubules and intermediate filaments

Question 18

Microfilaments

Answer 18

Made of solid polymerized rods of actin
Resistant to compression and fracture
Can use ATP to interact with myosin and generate force for movement
Forms the cleavage furrow in cytokinesis; pinches off the connection between daughter cells

Question 19

Cytokinesis

Answer 19

division of materials between daughter cells

Question 20

Microtubules

Answer 20

Hollow polymers of tubulin proteins
Roadways for motor proteins like kinesin and dynein carry vesicles
Cilia and Flagella are examples of microtubule structures

Question 21

9+2 structure

Answer 21

Found only in eukaryotic organelles of motility. 9 pairs of microtubules for an outer ring; 2 microtubles found in the center

Question 22

Intermediate filaments

Answer 22

Diverse group of filamentous proteins
Can withstand a lot of tension
increases structural rigidity and anchors cells and organelles

Question 23

Tissue (definition and types)

Answer 23

a collection of cells that work together; the cells may perform different functions to contribute to the main function of the tissue

Types: epithelial, connective, muscle, and nervous tissue

Question 24

Epithelial Tissue

Answer 24

Cover the body and line body cavities