Ch2 - Cytology Table 2-3

Question 1

Cell Membrane

Answer 1

fluid mosaic of lipid, protein, and carbohydrate components

Function: Physically surrounds cytoplasm and organelles, and controls substances entering/leaving the cell.

Question 2

Cytosol

Answer 2

fluid (mostly water) in which organelles are suspended.

Function: Serves as a medium in which chemical reactions occur.

Question 3

Nucleus

Answer 3

double-membrane-bound area (usually centrally located) which contains most of cellular DNA.

Function: Replicates prior to cell division (so that each daughter cell has a set of DNA) and serves as a template for the manufacture of RNA (transcription).

Question 4

Nucleolus

Answer 4

One of more dark staining areas within the nucleus

Function: Contains the DNA used to manufacture ribosomal RNA

Question 5

Chromatin

Answer 5

The combination of DNA and protein that forms the structure of chromosomes.

Function: Replicates before a cell divides and condenses to form chromosomes (heterochromatin). More commonly involved in the manufacture of RNA in a less organized form called euchromatin.

Question 6

Mitochondria

Answer 6

Double membrane bound organelles with highly folded inner membranes

Function: Contain enzymes and coenzymes involved in oxidative phosphorylation/electron transport reactions (i.e., they produce ATP).

Question 7

Ribosomes

Answer 7

Structures composed of protein and ribosomal RNA

Function: Serve as the site of protein synthesis by “reading” the codes (three basic sequences) on messenger RNA.

Question 8

Golgi Complex

Answer 8

Series of double membrane sacs and vesicles near the nucleus and connected to the endoplasmic reticulum

Function: Produced carbohydrates and glycoproteins and modifies and packages materials for cellular secretion.

Question 9

Endoplasmic reticulum

Answer 9

Double membranes extending throughout the cytosol from the nucleus to the cell membrane

Function: When ribosomes bind to it (rough endoplasmic reticulum = RER), it channels the proteins produced by the ribosomes to the golgi complex to be packaged for exocytosis. Without ribosomes (smooth endoplasmic reticulum = SER), ER is involved in lipid synthesis and detoxification reactions.

Question 10

Lysosome

Answer 10

Single-membrane-bound cytoplasmic sacs containing hydrolytic enzymes.

Function: Fuse to other cytoplasmic structures in order to digest phago-cytized material or hydrolyze worn out cell parts.

Question 11

Vacuoles (vesicles)

Answer 11

Single-membrane-bound cytoplasmic sacs that may contain a variety of materials.

Function: Often consists of recently endocytosed material awaiting lysosomic degradation or material to be exocytosed. Any (single) membrane-bound structure that cannot be specifically identified is termed a vacuole

Question 12

Peroxisomes

Answer 12

Single-membrane-bound cytoplasmic sacs containing enzymes capable of producing hydrogen peroxide (H2O2)

Function: Produce hydrogen peroxide and use it in oxidation reactions.

Question 13

Centrioles

Answer 13

A pair of microtubular structures located in an area near the nucleus called the centrosome

Function: Organize the cellular microtubular structures and attach via them to the chromosomes during cellular division

Question 14

Cilia

Answer 14

Hair-like projections of the cell membrane of some cells

Function: Can “beat” or “wave” in a coordinated fashion to move material along the cell’s surface

Question 15

Flagellum

Answer 15

A single, elongated cilium-like projection forming the tail of a sperm.

Function: Propels sperm forward in a “swimming-like” manner.

Question 16

Microvilli

Answer 16

Cell membrane projections similar in appearance to cilia but much smaller and immobile

Function: Increase the cell surface area to increase the efficiency of absorption

Question 17

Microfilaments

Answer 17

Tiny, non-tubular filaments formed of protein

Function: Involved in cellular “contractions” and amoeboid movements.

Question 18

Microtubules

Answer 18

Tubular structures that extend throughout the cytosol

Function: Form the central parts of cilia, flagella, and the spindle apparatus involved in chromosomal organization during cell division.