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BLG 143 Chapter 1 > Chapter 1 > Flashcards

Chapter 1 Flashcards

1
Q

What is an organism

A

An organism is a life-form—a living entity made up of one or
more cells

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2
Q

Three of the greatest unifying ideas in all of science, which
depend on the five characteristics just listed, laid the groundwork for modern biology, are

A

the cell theory, the theory of evolution,
and the chromosome theory of inheritance

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3
Q

An explanation for a very general class of phenomena or observations that is supported by a wide body of
evidence is a

A

Theory

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4
Q

All living organisms share 5 characteristics, which are:

A
  1. Cells (Cell Theory - Robert Hooke and Anton van Leeuwenhoek, late 1660s). All organisms are made of membrane-bound cells
  2. Replication. All organisms are capable of reproduction
  3. Evolution (Theory of evolution by natural selection -
    Charles Darwin and Alfred Russel Wallace, 1850s). Populations of organisms are continually evolving.
  4. Information. All organisms process hereditary information encoded in
    genes as well as information from the environment (The chromosome theory of inheritance - Walter Sutton
    and Theodor Boveri, 1902)
  5. Energy. All organisms acquire and use energy
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5
Q

A hypothesis is a

A

Testable statement that explains
something observed

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6
Q

A prediction is a

A

Measurable or observable result that
must be correct if a hypothesis is valid

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7
Q

What allows researchers to test the effect of a factor on a particular phenomenon

A

An experiment

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8
Q

Louis Pasteur’s hypothesis (fundamental to Cell Theory) states that

A

– Cells arise from cells
– Cells do not arise by spontaneous generation

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9
Q

How did Louis Pasteur test his hypothesis

A

He placed the broth in a straight necked flask and a swan necked flask. He boiled to sterilize the flask. In the straight necked flask, preexisting cells enters from the air. In the swan necked flask, pre-existing cells were trapped in neck so no new cells enter the flask. In the swan-necked flask, no new cells were created.

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10
Q

In 1858, which two scientists made the following claims:
1. All species are related by common ancestry. A species is a distinct, identifiable type of organism
2. Characteristics of species can be modified from generation to generation. This was referred to by one of the scientists as called this descent with modification

A

Charles Darwin and Alfred Russel
Wallace

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11
Q

What is defined as:
– is a change in the characteristics of a population over
time.
– It means that species are related to one another and
can change through time.

A

Evolution

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12
Q

A population is

A

– A group of individuals of the same species
– Living in the same area
– At the same time

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13
Q

What is used to explain how evolution occurs

A

Natural selection

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14
Q

Two conditions must be met for natural selection to occur in a population:

A
  1. Individuals must vary in characteristics that are
    heritable—can be passed on
  2. In a particular environment, certain versions of these
    heritable traits help individuals reproduce more than
    other versions
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15
Q

If certain heritable traits lead to increased success in producing offspring, what happens

A

These traits become more common in the population over time. In this way, the population’s characteristics change as a result of natural selection acting on individuals

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16
Q

Natural selection acts on

A

Individuals

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17
Q

Evolutionary change occurs in

A

Populations

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18
Q

Speciation occurs when

A

populations diverge to form new
species

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19
Q

What is defined as:
– The ability of an individual to produce offspring.
– Individuals with high fitness produce many surviving
offspring

A

Fitness

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20
Q

Adaptation is

A

A trait that increases the fitness of an individual in a
particular environment

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21
Q

The chromosome theory of inheritance explains

A
  • What is the source of heritable variation in traits?
  • How is information stored and transmitted from
    one generation to the next?
  • third unifying idea of biology
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22
Q

Chromosomal theory of inheritance proposed in 1902 by

A

Walter Sutton and Theodor Boveri

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23
Q

Chromosomal theory states

A

– Hereditary or genetic information is encoded in genes
– Genes are units located on chromosomes

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24
Q

In the 1950s, what information was added to the chromosomal theory

A
  • chromosomes are molecules of
    deoxyribonucleic acid, or DNA
    – DNA is the hereditary material
    – Genes are segments of DNA that code for cell products
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25
Q

Each strand of the double helix is made up of four building blocks:

A

A, T, C, and G

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26
Q

DNA carries, or encodes, information needed for an organism’s

A

growth and reproduction

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27
Q

The two strands of the double helix are
held together by connections between the building blocks. The pairings are

A

– A pairs with T
– C pairs with G

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28
Q

The pairings in DNA allows

A

DNA to be copied, and preserves the information encoded in the
DNA

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29
Q

Who proposed that DNA is a double-stranded helix

A

James Watson and Francis Crick

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30
Q

What is the central dogma

A
  • Describes the flow of
    information in cells
  • DNA codes for ribonucleic
    acid, or RNA, which codes
    for proteins
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31
Q

RNA copy is made of

A

the DNA’s information

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32
Q

The RNA copy is read to
determine

A

what building blocks to use to make a
protein

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33
Q

Why is DNA copied

A

to pass genetic information from
cell to cell or from one organism to its offspring

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34
Q

Copying DNA is highly

A

Accurate

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35
Q

What happens when a mistake is made in copying DNA?

A

– DNA sequence changes may lead to changes in
proteins
– Outward appearance is a product of proteins produced
– DNA sequence changes may cause changes in
outward appearance

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36
Q

At an individual level, what may increase or decrease fitness

A

Changes in DNA sequence

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37
Q

At population level, changes in DNA sequence may

A

– Lead to heritable variations that underlie diversity of life
– Make evolution possible

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38
Q

Where do the chemical reactions that sustain the diversity of life take place

A

inside cells and requires energy

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39
Q

Organisms have two fundamental nutritional needs:

A
  1. Acquiring chemical energy in the form of adenosine
    triphosphate (ATP)
  2. Obtaining molecules that can be used as building
    blocks to make DNA, RNA, proteins, etc
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40
Q

What is central to the diversification of life

A

How organisms acquire energy

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41
Q

What is a family tree of organisms that describes the
genealogical relationships among species with a single
ancestral species at its base

A

The Tree of Life

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42
Q

Phylogeny is

A

the actual genealogical relationships among all organisms

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43
Q

Biologists study RNA and DNA from different organisms to

A

– Compare sequences of the building blocks (A,T,C,G)
– Fewer sequence variations between two species may
indicate a closer relationship

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44
Q

A phylogenetic tree is used to

A

– Is used to show the relationships between species
– Branches that share a recent common ancestor
represent species that are closely related
– Branches that do not share recent common ancestors
represent species that are more distantly related

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45
Q

A phylogenetic tree is constructed using

A
  • sophisticated computer programs
    – arrangement of branches that is most consistent with
    the similarities and differences observed in the genetic
    data
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46
Q

The universal tree or tree of life includes

A
  • a diverse array of species
  • tree’s main node is the common ancestor of all living
    species
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47
Q

The Three Domains of Life
proposed by Carl Woese (1990) are

A
  1. bacteria
  2. Archaea
  3. Eukaryota
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48
Q

The tree of life shows

A

Fungi and animals are more closely related to each
other than either is to plants

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49
Q

Traditional classification schemes were often

A

Inaccurate

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50
Q

The location of certain branches on the tree of life is

A

hotly debated, and the shape of the tree will
continue to change as databases expand

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51
Q

The effort to name and classify organisms

A

Taxonomy

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52
Q

A taxon is

A

A named group

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53
Q

Who established the classification system in 1735 that is still in use today

A

Carolus Linnaeus

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54
Q

Each organism is given a unique two-part scientific name consisting of
the

A

genus and the species

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55
Q

What is made up of a closely related group of species.

A

Genus

56
Q

What is made up of individuals that regularly breed together or have
characteristics that are distinct from those of other species

A

Species

57
Q

Covalent bonds result from

A

electron sharing

58
Q

When two hydrogen atoms form a covalent bond

A

their unpaired valence electrons are shared by each nucleus

59
Q

What are substances held together by covalent bonds

A

Molecules

60
Q

What are molecules in which atoms of different elements are held together

A

Compounds

61
Q

Atoms may have different electronegativities, which is

A

the strength with which they pull electrons toward themselves

62
Q

Electronegativity is determined by

A
  • number of protons and the distance of the valence shell from the nucleus
  • In general, moving up and to the right on the periodic table = higher electronegativity
  • O > N > S,C,H,P
63
Q

Differences in electronegativity dictate how

A

electrons are distributed in covalent bonds

64
Q

What type of bond is this:
 Electrons are evenly shared between two atoms
 The bond is symmetrical
 Example: C–H bond

A

Non-polar covalent

65
Q

What type of bond is this:
 Electrons are shared unevenly
 Example: O–H bond

A

Polar covalent bond

66
Q

Water is polar (electrons are pulled towards oxygen), so which bonds form between water molecules

A

Hydrogen bonds

67
Q

Polarity (and, hence, water
solubility) is a function of

A

molecular shape and the
relative electronegativities
of atoms within the
molecule

68
Q

Ionic bonds result when

A

electrons are transferred from
one atom to another to give both atoms full valence shells

69
Q

An ion is an atom or molecule that

A

carries a charge

70
Q

An atom that loses an electron and becomes
positively charged

A

Cation

71
Q

An atom that gains an electron and becomes
negatively charged

A

Anion

72
Q

Ionic bonds are the attraction between

A

oppositely charged ions

73
Q

What is the electron sharing continuum

A
  • the degree of electron sharing in chemical bonds can be thought as a continuum, from equal sharing in nonpolar covalent bonds to complete electron transfer in ionic bonds.
  • Nonpolar covalent bonds (atoms have no charge), polar covalent bonds (atoms have partial charge), ionic bonds (atoms have full charge).
74
Q

Describe how water participates in hydrogen bonds

A
  • Water is polar
  • The polar covalent bonds in water give the oxygen a partial negative charge and each hydrogen atom a partial positive charge
  • The partial charges on water molecules can form up to four hydrogen bonds. The oxygen can form two; each hydrogen can form one.
75
Q

Hydrogen bonds can also form between a water molecule
and

A

Any other polar molecule

76
Q

Hydrophilic (“water-loving”) atoms and molecules

A

– Are ions and polar molecules that stay in solution
– They interact with water’s partial charges

77
Q

What makes it possible for almost any
charged or polar molecule to dissolve in water

A

Hydrogen bonding

78
Q

Polar molecules and ionic compounds dissolve regularly in

A

water

79
Q

Hydrophobic (“water-fearing”) molecules are

A

– Are uncharged and non-polar compounds
– They do not dissolve in water

80
Q

Hydrophobic molecules interact with each other through

A

hydrophobic interactions

81
Q

Which molecules do not dissolve in water

A
  • Nonpolar molecules
  • In aqueous solution, nonpolar molecules are forced to interact with themselves
  • This occurs because water is much more stable when it interacts with itself rather than with the nonpolar molecules
82
Q

In terms of solubility in water, carbohydrates

A

vary

83
Q

Water has several remarkable properties, largely due
to its ability to form hydrogen bonds, they include

A
  1. Cohesive
  2. Adhesive
  3. Denser as a liquid than a solid
  4. Able to absorb large amounts of energy
84
Q

Cohesion is

A
  • binding between like
    molecules
    – Water binds to itself by hydrogen
    bonding
    – Results in high surface tension
85
Q

Adhesion is

A
  • binding between unlike
    molecules
    – Water binds to plastic or glass
    – Results in capillary action and
    meniscus formation
86
Q

Why does water in a glass form a dip in the middle

A
  • water moleucles in a glass at the surface form hydrogen bonds with nearby water molecules and resist the upward pull of adhesion
  • water molecules that adhere to the glass pull upward at the perimeter
87
Q

Why do light objects not fall through the waters surface

A

Surface tension

88
Q

Water resists forces that

A

increase its surface area

89
Q

In ice water molecules form a

A

Crystal lattice due to bonding

90
Q

In liquid water, no lattice develops because

A

As a liquid, bonds are continually breaking

91
Q

Why does ice float

A

Liquid water is less dense than ice

92
Q

Water molecules dissociate into

A

a hydrogen ion (H+) and
a hydroxide ion (OH−)

93
Q

chemical equilibrium is when

A

Reaction happens in both directions at approximately the same
rate (e.g dissociation of water)

94
Q

Since protons (H+) don’t exist by themselves, the reaction
actually produces

A

hydronium ions (H3O+)

95
Q

Which substances give up protons during chemical reactions and raise the hydronium ion concentration [H3O+]

A

Acids

96
Q

Adding an acid to a solution increases the concentration what in the solution

A

Proton concentration increases

97
Q

What are substances that acquire protons during chemical reactions and lower [H3O+]

A

Bases

98
Q

Adding a base to a solution decreases what concentration in a solution

A

Proton

99
Q

The molecular weight of a molecule is

A

the sum of the atomic weights of all the atoms in the molecule

100
Q

Which unit of measurement:
– Equals 6.022 × 1023 molecules
– Has a mass equal to the molecular weight expressed in
grams

A

A mole

101
Q

The concentration of a substance in a solution is typically
expressed as

A

Molarity (moles/liter)

102
Q

What determines how acid base reactions occur

A

Number of protons

103
Q

The pH scale expresses

A
  • proton concentration [H+] in a
    solution
    – Negative base 10 logarithmic scale
    – pH of water is 7
104
Q

What is the role of a buffer

A
  • Buffers protect against changes in pH
    – Life is sensitive to pH
105
Q

Buffers allow for relatively constant conditions, this is known as

A

Homeostasis

106
Q

Changes in proton concentration affect the structure and
function of

A
  • polar or charged substances
    – As well as the tendency of acid–base reactions to
    occur
107
Q

What works as a buffer in blood

A

Carbonic acid. Disassociation of carbonic acid in an aqueous
solution to form bicarbonate ions and protons

108
Q

The capacity to do work or supply heat is known as

A

Energy

109
Q

What are the two types of energy

A
  1. Potential energy—stored potential to do work
  2. Kinetic energy—active energy of movement
110
Q

In molecules, potential energy is related to the position of

A
  • shared electrons in covalent bonds
111
Q

If the shared electrons are far from the atoms’ nuclei, the bonds are

A

the bonds are long and weak

112
Q

If the electrons are shifted closer to one or both nuclei, the bonds are

A

the bond becomes shorter and stronger

113
Q

A molecule’s potential to form stronger bonds is a type of
potential energy called

A

Chemical energy

114
Q

Do highly electronegative particles such as oxygen increase or decrease potential energy

A

Highly electronegative atoms pull shared electrons closer to their own nuclei, increasing bond strength and decreasing potential energy

115
Q

Do less electronegative particles such as carbon and hydrogen increase or decrease potential energy

A

They share electrons more equally, decreasing bond strength and increasing potential energy

116
Q

The kinetic energy of molecular motion is called

A

Thermal energy

117
Q

What is a measure of the thermal energy in a molecule

A

Temperature

118
Q

If an object has a low temperature, its molecules are
moving

A

Slowly

119
Q

If an object has a high temperature, its molecules are
moving

A

rapidly

120
Q

What is a measure of thermal energy being transferred
between two objects

A

heat

121
Q

What is the first law of thermodynamics

A

– Energy is conserved
– It cannot be created or destroyed
– It can be transferred or transformed

122
Q

Chemical reactions are spontaneous if

A

– They proceed without any continuous external
influence
– No added energy is needed

123
Q

Spontaneity of a reaction is determined by two factors

A
  1. Products are less ordered than the reactants
     Entropy (disorder) increases
  2. Products have lower potential energy than the reactants (shared electrons are held more tightly than in the reactants)
124
Q

When hydrogen and oxygen has react, the products have

A

Lower potential energy than the reactants. In the products, electrons are held loosely in bonds between atoms of equal electronegativities. For the reactants, electrons are held tightly by highly electronegative atoms, such as the oxygen. As a result, potential energy drops

125
Q

The second law of thermodynamics states that

A

– Entropy always increases
– Chemical reactions result in products with
 Less ordered energy
 Less usable energy

126
Q

Physical and chemical processes proceed in the direction that results in

A

lower potential energy and increased disorder

127
Q

Why is carbon is the most versatile atom on Earth

A

– Because of its four valence electrons
– Because it can form many covalent bonds

128
Q

Organic compounds are molecules that contain

A
  • carbon bonded to other elements
    – An almost limitless array of molecular shapes
    – With different combinations of single and double bonds
129
Q

The formation of carbon–carbon bonds was an important event in

A

Chemical evolution

130
Q

functional groups are

A

important H-, N-, O-, P-, and S-containing groups found in organic compounds

131
Q

Which functional group attracts a proton and act as bases

A

Amino (amines) group

132
Q

Which functional group drops a proton, and act as acids

A

carboxyl (carboxylic acids)

133
Q

Which functional group has sites that link molecules into larger, more-complex compounds

A

Carbonyl groups (aldehydes and ketones). Aldehydes especially react with certain compounds to form larger compounds.

134
Q

Which functional group acts as weak acids

A

hydroxyl (alcohols)

135
Q

Which functional group has two negative charges

A

Phosphate groups (organic phosphates)

136
Q

Which functional group links together via disulphide bonds

A

Sulfhydryl groups (thiols)

BLG 143 Chapter 1 (5 decks)

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