The Cell

Question 1

Totipotent

Answer 1

ability to differentiate into any cell in the body, eg. zygote

Question 2

Nuclear envelope

Answer 2

double membrane, pores, continuous with RER

Question 3

Nucleolus

Answer 3

spherical, dark body

Question 4

Chromatin

Answer 4

compacted DNA wrapped around proteins, packs into chromosomes

Question 5

Euchromatin

Answer 5

lightly stained, ACTIVE

Question 6

Heterochromatin

Answer 6

intensely stained, INACTIVE

Question 7

Process of transcription

Answer 7

DNA uncoils, sequence exposed, mRNA assembled by enzymes, sequence complementary to DNA, mRNA strand moves into cytoplasm through nuclear pore

Question 8

Process of translation

Answer 8

mRNA binds to ribosomal unit and is decoded, tRNA aligns amino acids to make polypeptide chain

Question 9

Cytosol

Answer 9

intracellular fluid, 75-90% water, 10-25% ions, glucose, amino acids, fatty acids, proteins, lipids, ATP, waste products

Question 10

Ribosome

Answer 10

2 subunits (small and large), site of protein synthesis, high RNA content, free and attached to ER

Question 11

Smooth endoplasmic reticulum

Answer 11

synthesis lipids (fatty acids and steroids)

Question 12

Golgi body (structure)

Answer 12

3-20 cisternae (small, flattened membranous sacs), entry (cis cisternae), exit (trans cisternae)

Question 13

Vesicles

Answer 13

membrane bound, carriers

Question 14

Mitochondria

Answer 14

double membrane, site of most ATP production, contains own DNA, can self-replicate

Question 15

Lysosomes

Answer 15

contains enzymes that work best at pH<5

Question 16

Microvilli

Answer 16

increase surface area, eg. digestive tract

Question 17

Cilia

Answer 17

move fluid-like along cell surface, eg. respiratory tract

Question 18

Flagella

Answer 18

move entire cell, eg. sperm

Question 19

Anchoring proteins

Answer 19

attach plasma membrane to other structures

Question 20

Recognition proteins

Answer 20

detected by cells of the immune system

Question 21

Receptor proteins

Answer 21

bind to specific extracellular molecules called ligands (eg. ion or hormone)

Question 22

Carrier protein

Answer 22

binds solutes and transports across plasma membrane

Question 23

Protein channels

Answer 23

integral proteins containing a central pore forming a passageway across membrane

Question 24

Diffusion (what substances)

Answer 24

fat soluble

Question 25

Facilitated diffusion

Answer 25

via protein carrier (eg. pump or channel)

Question 26

Osmosis

Answer 26

water

Question 27

Three stages of cellular communication

Answer 27

1. reception 2. transduction (relay molecules in signal pathway) 3. response (activation of cellular response)

Question 28

Stages of mitosis

Answer 28

interphase, prophase, metaphase, anaphase, telophase

Question 29

Interphase (including G0, G1, S, G2)

Answer 29

preparation for division G0 (G naught) - normal cell function G1 - cell function, generation of organelles S phase - duplication of chromosomes, DNA replication, synthesis of histones and nuclear proteins G2 - protein synthesis, centriole replication

Question 30

Prophase

Answer 30

early - DNA uncoils/chromatin condenses - nuclear membrane disappears late - centrosomes migrate to poles

Question 31

Metaphase

Answer 31

chromosomes align along metaphase plate, attached to microtubules held by centrioles

Question 32

Anaphase

Answer 32

microtubules pull chromatids away from centre

Question 33

Telophase

Answer 33

nuclear envelope reforms, DNA uncoils

Question 34

Cytokinesis

Answer 34

cytoplasmic division of daughter cells

Question 35

Cyclins

Answer 35

family of proteins involved in regulation of cell cycle

Question 36

Apoptosis (what and why)

Answer 36

programmed cell death, intracellular processes (internal DNA damage, death receptor), cleared by macrophages, phagocytosis

Question 37

Necrosis (what)

Answer 37

unplanned cell death, external stressors, blebbing (cell membrane fragments, swelling, nuclear fragmentation, cell rupture)

Question 38

4 types of necrosis

Answer 38

1. coagulative - protein denatured but shape maintained 2. liquefactive - rapid lysis of cells by lysosomal degradation enzymes 3. caseous - coagulative + liquefactive 4. gangrenous - caused by ischemia (no blood supply) to large amount of tissue