ch. 2 cellular and molecular physiology

Question 1

carbohydrates

Answer 1

monosaccharides [ie glucose] & polysaccharides [ie glycogen, cellulose]

Question 2

lipids

Answer 2

fatty acids, phospholipids, cholesterol

Question 3

proteins

Answer 3

composed of amino acids

highly complex 3d structures

Question 4

nucleic acids

Answer 4

composed of nucleotides

deoxyribonucleic acid [DNA]

ribonucleic acid [RNA]

Question 5

major subdivisions of eukaryotic cells

Answer 5

plasma membrane [cell membrane] - separates cell’s contents from the surrounding environment & selectively controls movement of molecules between intracellular fluid [ICF] and extracellular fluid [ECF]

nucleus - contains DNA; materials for genetic instructions and inheritance& control center of the cell

cytoplasm - contains organelles and cytoskeleton dispersed within the cytosol

Question 6

DNA

Answer 6

packed with histones to form chromosomes

contains codes [genes] for making RNAs and proteins through transcription and translation

functions:
provide a code of info for RNA & protein synthesis

serves as a genetic blueprint during cell replication

Question 7

transcription

Answer 7

gene is copied into a pre-messenger RNA by RNA polymerase

pre-messenger RNA is processed into messenger RNA [mRNA] by removing noncoding sequences and adding signal sequences

Question 8

translation

Answer 8

mRNA leaves the nucleus and delivers a coded message to a ribosome

ribosomal RNA [rRNA] translates the mRNA code into amino acid sequences

transfer RNA [tRNA] transfers the appropriate amino acids from cytoplasm to ribosome to be added to the protein under construction

Question 9

endoplasmic reticulum [ER]

Answer 9

elaborate, fluid-filled membranous system distributed throughout the cytoplasm

Question 10

rough ER

Answer 10

ribosomes bound to the outer surface give rough ER its granular appearances

new proteins synthesized by ribosomes are released into lumen of rough ER

Question 11

smooth ER

Answer 11

no ribosomes

synthesis of lipids [ie steroid hormones]

detoxify toxic compounds in liver cells

Question 12

ribosomes

Answer 12

synthesize proteins under direction of nuclear DNA

free ribosomes dispersed throughout cytosol

bound ribosomes are found on membranes of rough ER

Question 13

golgi complex

Answer 13

newly synthesized molecules from smooth ER enter

modifies proteins to final form

sorts finished products and directs them to final destination

Question 14

lysosomes

Answer 14

break down organic molecules

contain hydrolases, enzymes that catalyze hydrolysis reactions

remove worn-out organelles

Question 15

process of endocytosis

Answer 15

pinocytosis, receptor mediated endocytosis, phagocytosis

Question 16

proteosomes

Answer 16

break down internal proteins into amino acids

Question 17

peroxisomes

Answer 17

membrane-enclosed sacs smaller than lysosomes

contain oxidative enzymes

Question 18

mitochondria

Answer 18

power plants of the cell, produce 90% of energy cells need

Question 19

aerobic vs anaerobic

Answer 19

aerobic pathways require consumption of O2

anaerobic pathways can proceed in absence of O2

Question 20

major steps in generation of ATP

Answer 20

glycolysis

citric acid cycle

electron transport chain associated with oxidative phosphorylation

Question 21

ATP [adenosine triphosphate]

Answer 21

carries high-energy bond in the terminal phosphate

Question 22

glycolysis

Answer 22

chemical process that breaks down glucose into two pyruvate molecules

can proceed in anaerobic conditions [no O2]

releases 2 electrons that are transferred to NAD+ to form NADH

not very efficient; 1 molecule of glucose yields 2 molecules of ATP

Question 23

citric acid cycle

Answer 23

key purpose of the cycle is to produce hydrogens for entry into the electron transport chain

cyclical series of 8 reactions catalyzed by enzymes in the mitochondrial matrix

pyruvate produced by glycolysis enters the mitochondrial matrix

pyruvate is converted to acetyl CoA by removal of a carbon and formation of CO2

acetyl CoA combines with oxaloacetic acid to form citric acid

2 carbons released for each turn of the cycle

Question 24

electron transport chain [respiratory chain]

Answer 24

electron carrier molecules are located in inner mitochondrial membrane

electrons are transferred through chain of reactions with electrons falling to lower energy levels at each step

O2 is final electron acceptor of the electron transport chain; O2 combines with electrons and hydrogen to form H2O

some energy released during transfer of electrons is used to synthesize ATP

total ATP yield is 30 ATPs per molecule of glucose

food + O2 => CO2 + H2O + ATP

Question 25

tolerance of O2 deficiency varies

Answer 25

obligate aerobes - requires O2 continuously for survival [mammals]

facultative anaerobes - can adapt to anaerobic conditions for days or months [brine shrimp embryos]

obligate anaerobes - thrive in anaerobic conditions

Question 26

vaults

Answer 26

hollow, octagonal organelles capable of docking with nuclear pores

Question 27

cytosol

Answer 27

highly organized, gelatinous mass surrounding the organelles in the cytoplasm

Question 28

centrosome

Answer 28

cell’s microtubule organizing center

Question 29

cytoskeleton

Answer 29

provides an intracellular scaffolding to support and organize cell’s components and control their movement

Question 30

cells are held together by

Answer 30

cell adhesion molecules [in plasma membranes]

extracellular matrix [biological glue, interstitial fluid]

cell junctions [specialized]

Question 31

specialized cell junctions

Answer 31

desmosomes - adhering junctions; anchor 2 closely adjacent cells

tight junctions - impermeable junctions; join sheets of epithelial tissue, prevents materials from passing between cells

gap