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Flashcards in Exam 2 Review Deck (140):
1

What is a gene?

a locus (region) of DNA that encodes a functional RNA or protein product, it is also the molecular unit for heredity

2

What is the molecular unit for heredity?

a gene (the smallest unit of measurement)

3

What is a polypeptide?

a chain of amino acids, proteins are made up of one or more polypeptide molecules

4

Amino acids are linked _____ in _____ bonds in order to form a polypeptide.

covalently, peptide

5

What are the subunits of proteins?

amino acids

6

What are the 5 main functions of nucleic acids?

heredity (store and transport information), cell control, energy storage, electron carriers, and signaling (i.e. DNA and RNA)

7

What is the central dogma of molecular biology?

DNA can be copied into DNA (replication). DNA codes for RNA, which codes for proteins. DNA is responsible for heredity (passing of traits onto offspring). It contains the instructions for building RNA and proteins, which make up the structure of the body and carry out most of its functions.

8

What is the coding of DNA to RNA called?

transcription

9

What is the coding of RNA to a protein called?

translation

10

What is the process of DNA creating more DNA?

DNA replication

11

What is a macromolecule?

a series of small subunits covalently bonded to form a larger molecule

12

What is a monomer?

one subunit (relatively small molecule)

13

What is a dimer?

two subunits

14

What is a trimer?

three subunits

15

What is a tetramer?

four subunits

16

What are the subunits of lipids?

fatty acids and glycerol

17

What are the subunits of carbohydrates?

monosaccharides

18

What are the subunits of nucleic acids?

nucleotides

19

What are isomers? Give an example.

molecules that have the same chemical formula, but a different arrangement of atoms in space (fructose and glucose)

20

Plants store energy as _____ while animals store energy as _____.

starch, glycogen

21

What is a disaccharide?

a sugar composed of two monosaccharides

22

What are the three types of lipids?

triglycerides, phospholipids, and steroids

23

What is polymerization?

a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks

24

Subunits of a macromolecule are joined together in _____ bonds.

covalent

25

What type of reaction is responsible for the polymerization of the four main types of subunits/molecules?

a condensation reaction (a reaction accompanied with the formation of a water molecule, water is lost), also known as a "dehydration reaction"

26

What type of covalent bond do amino acids form?

peptide

27

What type of covalent bond do fatty acids and glycerol form?

ester

28

What type of covalent bond do monosaccharides form?

glycosidic

29

What type of covalent bond do nucleotides form?

phosphodiester

30

Are lipids hydrophobic or hydrophilic?

hydrophobic (not soluble in water)

31

What are triglycerides responsible for?

energy storage

32

What are phospholipids responsible for?

membranes

33

What are steroids responsible for?

signaling (hormones) and membranes

34

What are triglycerides responsible for?

energy storage

35

What are the components of a triglyceride?

one glycerol and three fatty acids

36

Within a triglyceride, each carbon atom will form exactly _____ bonds with other atoms.

four

37

What is a glycerol molecule?

three carbons and three hydroxyl (OH-) groups

38

What is a fatty acid?

chain of carbons (CH2) with carboxyl (COOH-) at one end, and CH3 on the other

39

What is a carboxyl group?

COOH-

40

How many carbons exist between the carboxyl and CH3 in a fatty acid?

10-40

41

Fatty acids are amphipathic, which means _____.

the two ends of the molecule differ in chemical properties

42

The hydrophilic part of a fatty acid consists of the _____ group, which means that this part of the molecule is _____.

carboxyl, polar (because water is polar, too)

43

The hydrophobic part of a fatty acid consists of a _____ chain and a _____ molecule, which means that this part of the molecule is _____.

carbon/hydrogen chain, CH3, nonpolar (because water is polar)

44

What does "saturated" mean when it comes to fatty acids?

hydrogen occupies all available bond space

45

What does "unsaturated" mean when it comes to fatty acids?

hydrogen does not occupy all available bond space

46

What forms if two adjacent carbons are missing hydrogen atoms within a fatty acid?

a double bond

47

Saturated fats are "regular," so they form _____.

tight crystals

48

Saturated fats have _____ melting points.

high

49

Unsaturated fats have _____ melting points.

low

50

What is a fatty acid "tail"?

string of carbons

51

Saturated fates have _____ bonded carbons because all of the bond space is occupied with hydrogen.

single

52

Unsaturated fats have _____ or _____ bonded carbons because not all of the bond space is occupied with hydrogen.

double, triple

53

Unsaturated fatty acids are usually in _____ form and have _____ tails.

liquid, short

54

Saturated fatty acids are usually in _____ form and have _____ tails.

solid, long

55

Amphipathic lipids form _____ in water.

micelles

56

What is a micelle?

a lipid molecule that arranges itself in a spherical form in an aqueous solution

57

An amphipathic lipid has a _____ head and a _____ tail.

hydrophilic, hydrophobic

58

What is the function of a phospholipid?

membranes

59

What happens when two hydroxyl groups meet of fatty acids?

The fatty acids bond, sharing the oxygen of one OH-, while the other becomes part of the water molecule that is lost.

60

What does a phospholipid consist of?

two fatty acid tails attached to the glycerol molecule, one phosphate (PO43-), and an R group

61

What does the "R" in "R group" stand for?

residue (as in an undefined molecular group, such as H, OH, CH3, etc.)

62

A phospholipid is has a _____ head and two _____ tails, which means that it is amphipathic.

hydrophilic, hydrophobic

63

Micelles _____ when they come into contact.

fuse

64

The fusing of micelles is a _____ process.

spontaneous

65

What is solubility of lipids in water determined by?

length of chains (tails), and saturation

66

Membranes in cells consist of _____ layers of phospholipids. This is called a singular _____ membrane. Understand this structure.

two, bilayer (hydrophilic heads face outward and inward toward the cell, and the hydrophobic tails face each other)

67

A double membrane consists of how many bilayers and how many phospholipid layers?

two, four

68

What is the "fluid mosaic model"?

the idea that membranes are fluid (with other components), to form a patchwork pattern of phospholipids with IMP's and PMP's scattered about

69

What is an integral membrane protein (IMP)?

a protein that spans the width of the membrane

70

What is a peripheral membrane protein (PMP)?

a protein that is embedded in the membrane but not all the way through

71

Name three functions of proteins.

channels (IMP), enzymes, and carriers

72

Membranes are fluid, so if they are pressed together, they will _____.

fuse

73

Name four things that will enhance the fluidity of a membrane.

warm temperatures, cholesterol, shorter fatty acid tails on the phospholipids, less saturation

74

Organic compounds always contain _____.

carbon

75

Micelles are specifically _____ molecules.

lipid

76

What are two of the functions of steroids?

increased membrane fluidity, hormones

77

What is the structure of a steroid?

ring structure, one carbon at every point of ring, other molecules also attached

78

What, specifically, is a hormone?

a steroid- signaling molecule that is derived from cholesterol

79

Is "equilibrium" synonymous to "equal distribution"?

no

80

How can you increase the rate of diffusion?

by adding energy

81

What does "turgid" mean?

swollen

82

Active transport requires _____.

energy (in the form of ATP)

83

What are the two major functions of macromolecules?

cytoskeleton (structural) and enzymes (functional)

84

What are the main three functions of enzymes?

catalysts, controls whether a reaction occurs, controls reaction speed

85

What are four important types of carbohydrates?

sugar, starch, glycogen, and cellulose

86

What are all membranes made out of?

lipids and proteins

87

More saturation results in _____ fluidity.

less

88

What are the two types of facilitated diffusion?

channel-mediated and carrier-mediated

89

What is simple diffusion?

random molecular movement so that eventually molecules become evenly distributed

90

What effect does energy have on simple diffusion?

it speeds up the process

91

Dialysis tubing is an example of a _____ or _____ permeable membrane.

selectively, differentially

92

What does tonicity mean?

concentration

93

What is plasmolysis?

the process of a cell using water in a hypertonic solution

94

The _____ is responsible for carrier-mediated diffusion.

peripheral membrane protein (PMP)

95

What is endocytosis? What effect does this have on the cell membrane?

movement into a cell, decreases the amount of cell membrane (vesicle used inside cell)

96

What is exocytosis? What effect does this have on the cell membrane?

movement out of a cell, increases the amount of cell membrane (vesicle that was used inside of cell becomes part of the membrane)

97

A _____ describes repeatedly dividing a cell.

clock

98

What is the clockwise "order" of components of the cell cycle clock, starting in the upper righthand corner?

G1 - S - G2 - M

99

What happens in G1?

this is "gap one," when the cell grows

100

What happens in S?

synthesis (DNA synthesis/replication)

101

What happens in G2?

this is "gap two," when the cell prepares for division

102

How can you describe, specifically, S (synthesis)?

single chromosome becomes double (they are both "one" chromosome, but with twice as much "stuff" after replication) -- 00 is one chromosome with one chromatid (monosome), 88 is one chromosome with 2 chromatids (disome)

103

What is the M phase on the cell cycle clock?

mitosis/meiosis

104

What is meiosis?

sexual reproduction, one nucleus becomes four, introduces variability (nuclei are not identical)

105

What is mitosis?

vegetative, somatic, asexual
responsible for growth, cell replacement, wound repair, hair and nail growth
results in two nuclei that are clones

106

What is cytokinesis?

the division of cell cytoplasm (may or may not occur after both meiosis and mitosis), the nuclei coexist in the cytoplasm until this occurs

107

What is G0?

Where cells go to no longer divide (outside of G1). They can pretty much enter and leave this state as they please.

108

The cell will divide if _____.

it passes the point of no return (a point on G2)

109

What is a "checkpoint" of cell division?

self-assessments to make sure the cell should divide (not going through the G2 checkpoint could result in cancer, where cell division is out of control)

110

What is a chromosome defined as?

one DNA molecule with its associated histone proteins (proteins that provide a "framework" for DNA to wrap around like a scarf)

111

How many types of histones are there?

five

112

What is an "interphase chromosome"?

one that is not wrapped or coiled tightly, it is invisible and called "chromatin," essentially an invisible blob

113

What happens to chromosomes during the "M phase"?

The chromosomes condense, making it easier for them to separate (rather than a glob, it's little 88 things)

114

What are the four main stages of mitosis, in order?

1. prophase
2. metaphase
3. anaphase
4. telophase
(PMAT?)

115

Describe what happens in the prophase of mitosis.

the centriole divides and migrates to the poles, the chromosomes condense, the nuclear envelope "disappears," and the spindle forms (microtubules (MTOC) and centrioles)

116

Describe what happens in the metaphase of mitosis.

chromosomes align at the equatorial plane and attach to the spindle

117

Describe what happens in the anaphase of mitosis.

the two halves of the chromosome separate, pulled by the spindle to opposite poles of the cell

118

Describe what happens in the telophase of mitosis.

the chromosomes have reached the poles of the cells, the nuclear envelope reforms, chromosomes decondense, the product is one cell with two nuclei (time for cytokinesis!)

119

How does cytokinesis work in bacteria?

no "M" phase because there is no nucleus, division in a process called "fission"

120

How does cytokinesis work in animal cells?

Furrowing- microtubules reorganize and pinch the cell in two

121

How does cytokinesis work in plants?

"phragmoplast" found in plants is used

122

What is the general structure of DNA?

DNA is a polymer of nucleotides, large subunits linked by covalent bonds (that are formed in the condensation/dehydration reaction)

123

What is the structure of a nucleotide?

sugar, phosphate, base

124

What does the sugar look like within a nucleotide?

5 carbons, ribose, deoxyribose (if it lost an oxygen)

125

Where is the phosphate molecule located within a nucleotide?

at carbon #5 (one of three phosphates is attached here)

126

What are the five possible bases of a nucleotide?

adenine, thymine, cytosine, guanisine, uracil (RNA only)

127

Where does the base attach within a nucleotide?

carbon number one

128

How are the carbons within a nucleotide ordered?

1-5 starting at the right upper corner and going clockwise

129

What is ATP as far as nucleotides go?

a nucleotide triphosphate

130

Which bases are pyrimidines?

cytosine, thymine, uracil

131

Which bases are purines?

adenine, guanisine

132

How does the polymerization of nucleotides work?

polymerization=chain building, from the 5' (front/phosphate) to 3' (tail) end

133

What is the result of the polymerization of nucleotides?

a DNA (sugar-phosphate) backbone

134

DNA is _____ stranded.

double

135

What type of bond holds the two DNA strands together?

hydrogen bonds

136

What stage of the cell cycle does DNA coil?

M phase

137

How many hydrogen bonds does the base pair A=T have?

two

138

How many hydrogen bonds does the base pair C=G have?

three

139

What does "denature" mean?

melt

140

How does DNA replication work?

occurs during the interphase (S phase), each half of the original DNA makes a copy, so each new DNA set has an old and new strand