1
Q
What are the five characteristics all living things share?
A
- All are composed of cells
- All can replicate/reproduce
- Replicating/reproducing/containing/processing/responding to information
- acquiring and using energy
- evolution
2
Q
Because scientific knowledge is based on evidence, previous ideas….
A
…..may be thrown out or changed due to new evidence
3
Q
How are theories similar and different from hypotheses?
A
Theories are like hypotheses in that they must be testable and falsifiable, but they are MUCH more
supported by evidence than are hypotheses (so, much less likely to be thrown out/changed) and
also more broad in scope
4
Q
How are theories different from laws?
A
They can be differentiated from laws in that they offer an explanation of the phenomenon
being studied, instead of just showing cause-and-effect relationships (laws are cause and effect)
5
Q
What are the 5 steps in the cycle of the scientific method?
A
- Observation
- Hypothesis
- Prediction
- Testing
- Conclusions
6
Q
Hypotheses must be ____ and _____ and are tentative (not certain or fixed) explanations of observations
A
Hypotheses must be testable and falsifiable and are tentative explanations of observations
7
Q
Hypotheses generally written in ____ tense
A
Hypotheses generally written in present tense
8
Q
Predictions outline how to ______; including what is manipulated by the experimenter
A
Predictions outline how to test the hypothesis, including what is being manipulated by the experimenter (independent variable) and what is expected to change (dependent variable)
9
Q
Predictions are in ____ tense and contain more _____ than hypotheses
A
Predictions are in future tense and contain more specifics than hypotheses
10
Q
Scientific studies undergo _____ ______ before being published
A
peer review
11
Q
What is a control group used for?
A
To to give something to compare against, as
well as help control for confounding variables
12
Q
What as a method of making a blind experiment?
A
Giving the control group a placebo
13
Q
What is a double blind experiment?
A
neither the person administering
the treatment nor the experimental subject know whether a placebo or actual treatment
was given
14
Q
Why is a double blind expirement the best expiremental design?
A
eliminates possible psychological effects and other confounding variables for both parties
15
Q
Why do experimental studies generally provide stronger evidence than observational studies?
A
Because the scientist manipulates the independent variable and can better control confounding variables, making cause-and-effect conclusions more reliable.
16
Q
Confounding Variable
A
Anything that may affect the experiment other than
the variable that you are manipulating (independent variable)
17
Q
How do non-polar covalent bonds share electrons?
A
Equal sharing
18
Q
How do polar covalent bonds share electrons? (is global warming fair to polar bears?)
A
Unequal sharing
19
Q
How do ionic bonds share electrons?
A
Complete transfer of electrons
20
Q
How do double bonds and triple bonds affect the strength of the bond within covalent bonds?
A
These are stronger/more rigid than single covalent bonds
21
Q
In covelent bonds more than one ______ pair may be shared making, double and triples covalent binds
A
electron pair
22
Q
What does unequal sharing or complete transfer of electrons led to?
A
to a partial or full charge on atoms (due to the negative charge of electrons)
23
Q
What is an ion?
A
A charged particle. An ion has lost or gained one or more electrons, giving it a charge
24
Q
Which biologocal molecules are usually nonpolar?
A
Biological molecules with mostly carbon and hydrogen are usually nonpolar
25
Which two elements make it more likely for a molecule to be polar?
The more oxygens and nitrogens there are in a biological molecule, the more likely it is
polar, especially in the region around those oxygens/nitrogens
26
Rank the 3 types of bonds based on strength from strongest to weakest
covalent bonds tend to be the strongest,
followed by ionic, and hydrogen bonds are very weak bonds
27
Why is water polar?
It forms hydrogen bonds with other water molecules as well as with other polar molecules
28
Water's polarity means that:
1. It tends to cohere to other water molecules and adhere to surfaces
2. It has a high capacity to absorb heat
29
When does hydrogen bonding occur?
where a partially charged hydrogen is attracted to another partial charge
(usually on oxygen or nitrogen)
30
What does it mean if something is Hydrophilic?
dissolve easily in water
31
What does it mean if something is Hydrophobic?
do not dissolve easily in water
32
Why are functional groups important?
Functional groups are frequently important to chemical behavior of a molecule and, thus, its
function
33
What is pH?
pH is a measure of acidity
34
What can chemical bonds store?
Energy
35
What is a Macromolecule?
Macromolecules are large molecules that often consist of several smaller subunits (called
monomers) bound together
36
What do carbohydrates consist of?
Carbohydrates consist most often of C, H, and O, usually in the ratio of about 1 C to 2 H to 1 O
37
What does the suffic "ose" indicate?
carbohydrates
38
Why can carbohydrates store energy?
Carbohydrates can store energy due to their large number of C-H and C-C nonpolar bond
39
Why are carbohydrates hydrophilic (dissolve easily in water)
They are also relatively hydrophilic because of their polar C=O and –O H functional groups
40
What are Monosaccharides?
Monosaccharides are the monomers of carbohydrates - all carbohydrates are made of one or more
monosaccharides
41
Name 3 important Monosaccharides
glucose, fructose, and galactose
42
Most monosaccharides exist in ______ and _____ structures. Which is most common?
Most monosaccharides exist in linear and ring structures, though in water (and thus most
biological systems), the ring structure is most common
43
How do different monosaccharides differ structurally?
They differ in the number of carbons (and therefore the number of hydrogens and oxygens).
44
Why does the number of carbons matter in monosaccharides?
The number of carbons determines the number of hydrogens and oxygens in the molecule.
45
Can isomers be different monosaccharides? Why?
Yes. Isomers can be different monosaccharides if the carbonyl (C=O) group is in a different position or if –OH groups are oriented differently.
46
What is the structural difference between glucose and fructose?
The carbonyl (C=O) group is in a different position.
47
What is the structural difference between glucose and galactose?
The –OH groups are oriented differently.
48
Can the same monosaccharide exist in different forms?
Yes. The same monosaccharide can form different ring structures depending on the orientation of a specific –OH group.
49
What is the difference between α-glucose and β-glucose?
They differ in the orientation (up vs down) of the –OH group attached to the first carbon.
50
Why are Monosaccharides important? (2 reasons)
The digestive system cannot absorb carbohydrates larger than a monosaccharide (larger
molecules must be broken down before absorbed)
* Monosaccharides (especially glucose) are used in cellular respiration
51
______ linkages covalenently-bound together Monosaccharides to form larger molecules
Monosaccharides may be covalently-bound together with glycosidic linkages to form larger
molecules
52
What are Disaccharides?
carbohydrates that consist of two monosaccharides
53
What are two examples of Disaccharides?
sucrose, lactose
54
What are Polysaccharides?
many monosaccharides covalently linked
55
Which polysaccharides are made of many linked glucose molecules?
Starch, glycogen, and cellulose
56
Why are starch, glycogen, and cellulose considered different if they’re all made of glucose?
he glucose molecules are arranged differently in each polysaccharide
57
What is the function of starch and glycogen?
Energy storage in plants.
58
What type of glucose is found in starch and glycogen?
α-glucose.
59
How do starch and glycogen differ structurally?
They differ in the amount of branching.
60
Why is glycogen digested faster than starch?
Glycogen is more highly branched, making it easier to break down.
61
Why do polysaccharides provide longer-lasting energy than mono- or disaccharides?
They must be broken down into smaller sugars before digestion, leading to slower, sustained energy release.
62
What is cellulose used for in plants?
Structural support.
63
Why can’t humans digest cellulose?
Cellulose is made of β-glucose, which forms a structure humans cannot break down.
64
How does β-glucose affect cellulose’s structure?
It causes glucose molecules to form linear, parallel strands.
65
What holds cellulose strands together?
Hydrogen bonds between parallel strands.
66
Name two other structural polysaccharides and where they are found.
Chitin: fungi and insects
Peptidoglycan: bacterial cell walls
67
Besides storing energy and structure, what else can carbohydrates be used for?
can be used in the making of other molecules and are important in cell-cell interactions
68
What are the monomers for proteins?
proteins are composed of amino acids
69
How can amino acids be identified?
Amino acids have a central carbon atom surrounded by an H, an amino (N H2), a carboxyl (C O O
H), and an R group/side chain
70
What is the function of the R-group in amino acids?
The R group is what differentiates different amino acids and gives them different properties
(acidic vs basic vs polar vs nonpolar, etc)
71
What are the four levels of protein structure?
1. Primary
2.Secondary
3. Tertiary
4. Quaternary
72
What is a primary protein structure?
a linear sequence of amino acids connected by covalent bonds (called peptide bonds)
between a C of one amino acid and the N of the next
73
What is a protein secondary structure?
due to hydrogen bonding between H of amino group and O of carboxyl group of nearby amino acids
74
What is a protein Tertiary structure?
due to interactions between R groups/side chains (H bonds, ionic,
covalent, hydrophobic interactions) or between side chains and amino acid “backbone”
75
What is a Quaternary protein structure?
more than one polypeptide
76
What determines three-dimensional shape of proteins
which determines protein function in proteins?
amino acid sequence
77
What causes proteinsto misfold? What does this lead to?
Prions cause proteins to misfold, leading to nervous tissue damage
78
What does denaturing a protein do?
Denaturing a protein (due to high temp or changes in chemical environment) usually disrupts
the three-dimensional structure (mostly, weaker bonds), but not the sequence of amino acids
(stronger bonds)
79
What functions do proteins serve in the body?
structure, protection/defense,
signaling, contraction/movement, and transport
80
What are enzymes?
proteins that catalyze/speed up chemical reactions – often building or
breaking down other molecules
81
What ending do enzymes often have?
Enzymes often have the ending “-ase”
82
What are essential amino acids?
are amino acids that cannot be produced by the human body and must be consumed in food for your body to be able to make all the proteins that it needs to make
83
What are the monomers for Nucleic acids?
Nucleic acids (e.g. DNA and RNA) are composed of nucleotides (monomer)
84
How do you identify nucleotides?
consist of a phosphate group, a 5-carbon sugar, and a nitrogenous base
85
How does the 5-carbon sugar differ between DNA and RNA?
DNA contains one less oxygen than RNA does
86
What makes nucleotides more reactive?
the addition of extra phosphate groups –
“activated” nucleotides
87
What is ATP?
an activated nucleotide that is the most commonly-used direct source of energy for
cells
88
Energy stored in glucose (and other macromolecules) is converted into energy stored in
______ before it can be used by cells
ATP
89
Nucleotides are connected with __________
phosphodiester linkages
90
Why are nucleotides added to the 3′ end of a growing DNA strand and not the 5′ end?
Because the free 3′-OH group allows the energy from activated nucleotides to form the new bond; the 5′ end lacks this reactive –OH and has an unlinked phosphate instead.
91
What is the backbone of nucleotides made of and connected by?
the
“backbone” of each strand of a nucleotides is sugars and phosphates connected via covalent
bonds
92
What are the two nucleotide stands in DNA connected by?
the two stands are connected by hydrogen bonds between nitrogenous bases
93
What are the uses for RNA?
One of the most important is that it is used as an
intermediate between DNA and protein during protein synthesis
Variety of structures leads to variety of functions, including acting as catalysts, like an enzyme
(ribozyme)
94
Why is RNA less stable than DNA?
Because of the –OH in the ribose structure, RNA is less stable than DNA
95
RNA is usually _______ standed
RNA is usually single-stranded
96
What are lipids characterized by?
Lipids are characterized by not dissolving well in water (unlike other macromolecules, they don’t
have monomers that characterize them)
97
What are the 3 main categories of Lipids?
triglycerides, steroids, and phospholipids
98
What is a Triglyceride
extremely non-polar lipids that are used as long-term energy storage (as
opposed to shorter-term energy storage in some polysaccharides, like glycogen in animals and
starch in plants).
99
Why are triglycerides nonploar?
Nonpolar because they mostly are made of C and H in nonpolar covalent bonds
100
What 3 fatty acids does glycerol in Triglycerides made of?
1.Saturated
2. Unsaturated
3. Trans
101
What are the characteristics of Saturated fats?
1. have no double bonds;
2.usually solid at room temperature because the straight
structure packs well;
3. often found in animal-based foods
102
What are the characteristics of Unsaturated fats?
1. have double bonds;
2. usually liquid at room temperature because the double
bonds form kinks;
3. often found in vegetable oils and fish oils (some of these cannot be made
by humans: “essential fatty acids”)
103
What are the characteristics of Trans fats
1. have double bonds, but are solid at room temperature because the double bond
doesn’t form a kink;
2. unnatural (found in highly-processed food) and hard to digest; indicated
by “partially hydrogenated vegetable oil” labels
104
Amphipathic molecules have polar/hydrophilic and non-polar/hydrophobic regions. They naturally form ______ because of this
membranes
105
What are steroids?
lipids composed of four linked carbon/hydrogen rings
106
What are Phospholipids composed of?
Phospholipids are composed of: a glycerol, two fatty acids, and head group that includes a
phosphate
107
Lipid bilayers are selectively ________ – only let certain molecules cross
selectively
108
________ almost never get through, even if they are small, unless they can go through lipid bilayer unless they go through a
protein channe
Charged ions
109
– the more ______ fatty
acids there are, the more permeable/fluid the membrane is
unsaturated
110
increased _______
increases permeability/fluidity
temperature
111
Atoms
Atoms: smallest unit with the properties of a given
element
112
electronegativity
The ability of an atom to attract electrons toward itself in a chemical bond
113
polar
Describes a bond or molecule in which electrons are shared unequally due to a difference in electronegativity, creating partial positive (δ⁺) and partial negative (δ⁻) charges.
114
nonpolar
Describes a bond or molecule in which electrons are shared equally because the atoms have similar or identical electronegativities, resulting in no partial charges.
115
Solvents
are liquids that solutes can dissolve into
116
R group
The variable group attached to the central carbon of an amino acid that determines the amino acid’s identity and chemical properties (such as polarity, charge, and hydrophobicity).
117
peptide bonds
bond that links amino acids together to form a protein (type of covalent bond)
118
Polypeptide
A chain of many amino acids linked together by peptide bonds. Polypeptides are the building blocks of proteins.
119
Denature/denaturation
loss of 3-dimensional shape (and thus
function) of a protein; sometimes reversible, sometimes not
120
Active site
location of catalysis from substrate(s) (The molecule upon which an enzyme acts in a chemical reaction) to product(s)
121
Cholesterol
a component of cell membranes; also modified to produce steroid hormones
122
Amphipathic
A molecule that has both a hydrophilic (water-loving) region and a hydrophobic (water-fearing) region.
123
Carbs functional group
1. 1 carbon to 2 hydrogen to1 oxygen ratio
2. many OH groups
124
Proteins functional group
1. amine group (N)
2. A hydrogen
3. Carboxyl group C=O
4. R-group
125
Nucleic acid functional group
1. Phosphate group
2. 5-carbon sugar
3. Nitrogenous base
Biology 1113
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