Lecture 4

Question 1

________: long chains of carbohydrate molecules,
composed of several smaller monosaccharides

Answer 1

polysaccharides

Question 2

__________: energy source and
source of carbon

Answer 2

Monosaccharides (simple sugars)

Question 3

________: polymers of monosaccharide units

Answer 3

Polysaccharides

Question 4

what are the two energy storing units of polysaccharides?

Answer 4

Glycogen in animal cells (branched) - primarily stored in liver and muscle cells

Starch in plant cells (mix of branch and unbranched
structures)

Question 5

________:
Linear polymer of several hundred to thousand glucose
units
Insoluble, rigid structural polymer
Makes up cell wall of plants

Answer 5

Cellulose

Question 6

why can’t humans digest cellulose?

Answer 6

The bonds differ from those of starch, we don’t have the enzymes to break down the specific glycolic bonds

Question 7

what are the three units of nucleotides?

Answer 7

nitrogenous base , pentose sugar, negatively charged phosphate group

Question 8

what are the three major cellular functions?

Answer 8

Nucleotides are monomeric units from which DNA and
RNA are made

Regulatory molecules

Agents of energy transfer for metabolism

Question 9

Second messengers in cell signaling (eg. cAMP) and
GTP can serve as a switch to activate some proteins (G-
proteins) are two of the functions of _________ as regulatory molecules

Answer 9

nucleotides

Question 10

Cleaving of phosphate groups releases energy (ATP) and
Co-enzymes in energy transfer reactions (NAD
are two of the functions of _________ as agents of energy transfer for metabolism

Answer 10

nucleotides

Question 11

The nucleotide subunits within
a DNA strand are held together
by ____________ bonds

Answer 11

phosphodiester

Question 12

true/false: RNA is always single-stranded

Answer 12

false, usually but not always

Question 13

true/false: RNA has 3-dimensional structure

Answer 13

true

Question 14

_______ are insoluble in H2 O but soluble in nonpolar organic liquids

Answer 14

lipids

Question 15

what is the biological role of lipids? (4 main roles)

Answer 15

• source of energy in the diet and serve to store energy in the body
• some hormones
• some vitamins
• The basic structural elements of biological membranes. Contains both hydrophobic and hydrophilic regions
  (amphipathic)

Question 16

true/false: A typical animal cell is 10–20 μm in diameter

Answer 16

true

Question 17

can we see atoms or molecules with a light microscope?

Answer 17

no! can’t see two objects separated by less than 200 nm

Question 18

what are the four types of commonly used microscopy?

Answer 18

Bright-field
Phase-contrast
Differential-interference-contrast
Fluorescence

Question 19

what is the advantage of light microscopy?

Answer 19

can look at live cells!

Question 20

true/false: Most cells are transparent and
mostly colorless - distinguishing the
internal structure of a cell is difficult

Answer 20

true

Question 21

_____________ molecules: absorb light at one wavelength and emit it at another, longer wavelength

Answer 21

fluorescent

Question 22

how do we view fluorescent stained organisms? through a fluorescence microscope

Answer 22

View it through a filter that allows only light of the emitted
wavelength to pass, so that it excites the particular fluorescent dye