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Cell Biology > Ch 2: Chemical Components of Cells > Flashcards

Ch 2: Chemical Components of Cells Flashcards

1
Q

What are the primary four elements that make up a cell’s mass?

A

C, H, N, O make up 96% of a cell’s mass

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2
Q

What determines the atomic number of an atom?

A

The number of electrons

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3
Q

What is the most abundant molecule in a cell?

A

Later makes up 70% of a cell’s mass

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4
Q

What are the main categories of molecules that make up a cell?

A

1) sugars
2) fatty acids
3) amino acids
4) nucleotides

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5
Q

Sugars overview

A

Primary source of chemical energy for cells

Join together to form polysaccharides or shorter oligosacchardes

Important for central metabolism in all organisms–we share the same process with everything, bacteria included

In water sugars tend to form into rings

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6
Q

Fatty acid overview

A

Rich energy source by primary role is to form lipids that assemble into cell membranes
Consists of a carboxylic acid (-COOH) (hydrophilic) attached to a long hydrocarbon chain (hydrophobic)
Starting point for the synthesis of phospholipids
When the hydrocarbon chain is missing and hydrogen and has a double-bond, the tail kinks and it is called unsaturated, and doesn’t pack as well together (more liquid at room temp)
When the hydrocarbon tail is full of hydrogen atoms and no double bonds the tails are straight and pack together well and are more likely to be solids

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7
Q

Macromolecules

A

The majority of the dry mass of a cell
Polymer molecule formed from covalently linked subunits of polysaccharides, proteins, and nucleic acids

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8
Q

Protein overview

A

Formed from 20 different types of amino acids covalently joined by peptide bonds into long polypeptide chains

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9
Q

Nucleotides overview

A

DNA, RNA, and energy-transfer reactions in cells
A nucleoside linked to a phosphate

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10
Q

How protein, DNA, and RNA are synthesized

A

Chained together from subunits by repetitive condensation reactions

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11
Q

Types of weak, non-covalent interactions in cells

A

1) hydrogen bonds
2) electrostatic attractions
3) van der Waals attractions
4) hydrophobic force

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12
Q

Acid

A

A molecule that releases a proton when dissolved in water
This generates hydronium ions (H3O +)
Lowers the ph

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13
Q

Amino acid

A

Contains:
- an amino group
- a carboxyl group
- an alpha-carbon
- a side chain
Serves as the building block of proteins
Life uses 20 amino acids

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14
Q

ATP

A

Activated carrier that is the main carrier of energy in cells
Nucleoside triphosphate composed of adenine, ribose, and three phosphate groups

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15
Q

Avogadro’s number

A

The number of molecules in a mole: 6x10^23
The quantity of a substance equal to its molecular weight in grams

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16
Q

Base

A

Molecule that accepts a proton when dissolved in water, creating OH- by removing the proton from water

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17
Q

Buffer

A

Mixture of weak acids and bases that maintains the ph of a solution by releasing and taking up protons

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18
Q

Chemical group

A

a combination of atoms such as a hydroxyl group (-OH) or an amino group (-NH2) with distinct chemical and physical properties that influences the behavior of the molecule in which it resides

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19
Q

condensation reaction

A

covalent bond that happens between two molecules that expels a water atom.
Used to build polymers such as proteins, polysaccharides, and nucleic acids

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20
Q

electronegativity

A

the tendency of an atom to attract electrons

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21
Q

Electrostatic Attraction

A

force the draws together oppositely charged atoms (ex ionic bonds and the attractions between molecules containing polar covalent bonds)

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22
Q

Hydrogen bond

A

weak non-covalent interaction between a positively charged hydrogen atom in one molecule and a negatively charged atom (such as oxygen or nitrogen) in another.
Key to the structure and properties of water

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23
Q

Hydrolysis

A

reaction that cleaves a covalent bond and consumes a water molecule–adds on -H to one end and an -OH to the other end
The reverse of a condensation reaction

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24
Q

hydronium ion

A

the form taken by a proton (H+) in an aqueous solution (H3O+)

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25
Hydrophobic force
non covalent interaction that forces together the hydrophobic portiosn of dissolved molecules to minimize the disruption of the hydrogen-bonded network of water causes phospholipids to form into a bilayer helps proteins fold into compact, globular shapes
26
Ionic Bond
when one atom donates an electron to another. Both atoms become electrically charged Atoms held together by ionic bonds are typically called salts rather than molecules
27
Lipid
organic molecule that is insoluble in water typically long hydrocarbon chains or multiple rings phospholipid is one class of lipid
28
Monomer
small molecule that can be linked to others of a similar type to form a larger molecule (polymer)
29
Polymer
Long molecule made by covalently linking multiple identical or similar subunits (monomers)
30
Protein
Macromolecule built from amino acids that provides cells with their shape and structure and performs most of their activities
31
RNA
Ribonucleic acid Molecule produced by the transcription of DNA, usually single-stranded, a polynucleotide composed of covalently linked ribonucleotide subunits. Performs informational, structures, catalytic, and regulatory functions in cells
32
van der Waals attraction
weak non-covalent interaction, due to fluctuating electrical charges that come into play between two atoms located very close to each other Can happen even between non-polar molecules
33
Why does Carbon play a unique role in the cell?
It's ability to form strong covalent bonds with other carbon atoms Just about all carbon molecules form four bonds. If there is a diagram with some missing, assume there are hydrogen atoms there that just aren't shown Carbon skeletons can form into chains, branched trees, and rings
34
Hydrocarbons
C-H compounds or groups made of carbon and hydrogen non-polar, so do not form polar bonds and are insoluble in water ex: methane, methyl group
35
CO compounds
-OH hydroxyl C=O carbonyl -COOH carboxyl (loses an H+ in water to become -COO-
36
Blank
Amines in water combine with H+ to become positively charged Amide formed by an acid and an amine, uncharged in water Nitrogen also forms into ring compounds such as purines and pyrimidines, which are important parts of nucleic acids
37
Formula/Structure of an amino acid
1) alpha carbon atom 2) amino group 3) carboxyl group 4) side chain
38
Phosphates in nucleotides
normally joined to the C-5 hydroxyl of the ribose or deoxyribose sugar can be mono, di, or tri Makes the nucleotide negatively charged
39
Nucleotide structure
a nitrogen-containing base, a five-carbon sugar (pentose), and one phosphate group
40
Nucleic Acids
nucleotides joined by phsophodiester bonds between the 5' and 3' carbon atoms of adjacent sugar rings formed by adding onto the 3' end Formed from: 1) base 2) phosphates 3) 5-carbon sugar (ribonucleic acid or deoxyribonucleic acid)
41
Phospholipid
Makes the phospholipid bilayer Hydrophilic head: a) polar group b) phosphate c) glycerol Two hydrophobic fatty acid tails
42
Bond strength
Different bonds have a different strength (different energy needed to break the bond)
43
Polypeptide chain
four atoms in each peptide bond starts at N terminus of polypeptide chain and the next attachment is at the C terminus
44
Nucleotide base
nitrogen-containing ring compounds, either pyrimidine (cytosine, thymine, uracil) or purine (adenine, guanine)
45
Other functions of nucleotides besides RNA and DNA
ATP: chemical energy Co-A combine with other groups to form enzymes cAMP: signaling molecule
46
Two general chemical rules
Opposite charges attract (electrostatics--enthalpy) oil and water don't mix (hydrophobic forces--entropy)
47
Energy and Catalysis
Catabolic pathways: break food down into: - useful forms of energy - lost heat - many building blocks for biosynthesis Anabolic pathways: take energy and building blocks and turn them into the molecules that form cells
48
Free Energy change
determines whether a reaction can happen spontaneously - there is an activation barrier to the reaction - enzymes lower the activation energy for a catalyzed reaction Free energy determines the relative amounts of starting paterial and product (delta G) -catalysts don't change the final concentration, only how quickly the changes can happen - sequential changes add delta G values, and allow a favorable reaction to drive an unfavorable one
49
Activated carrier molecule
Holds onto energy in the form of chemical bonds Most common one is ATP
50
Protein Synthesis
Goes from N-terminus of polypeptide chain to C-terminus of polypeptide chain Linked by peptide bonds
51
Blank
1) Uncharged polar side chains 2) Non-polar side chains 3)
52
How is biological order made possible?
The release of heat energy from cells increases entropy as the cells create order
53
What is the sugar group that is found in RNA?
ribose sugar, in contrast to the deoxyribose sugar found in DNA. Ribose sugar has 1 more hydroxyl group on 2' carbon than deoxyribose sugar.
54
In addition to the DNA and genome, what other important biological molecules are nucleotides part of?
ATP
55
What kind of molecule does this picture represent? What are the different components called?
Phospholipid from the bottom up: - fatty acid chain - glycerol - phosphate group - polar head group
56
What kind of molecule is this? Name all parts on the molecule
Amino acid molecule Left-->right: amino group, alpha carbon, side chain, and carboxylic acid group.
57
What part of the molecule is charged?
the phosphate group is negatively charged
58
What direction does DNA synthesize from? What direction does protein synthesize from?
DNA: 5' to 3' Protein: N-terminus to C-terminus
59
Explain what catalysts do in terms of energy diagram Do catalysts change the delta G of the reaction?
Catalysts lower the activation energy of a reaction, and do not change the delta G of a reaction
60
What is the second law of thermodynamics and how to organized life forms deal with the second law?
A system always moves towards greater entropy. Life forms deal with this by releasing heat during their reactions
61
Nucleoside
a base plus its sugar with no phosphate group attached
62
Why can scientists substitute radioisotopes for isotopes commonly found in cells when conducting experiments?
Radioisotopes of an element differ only in the number of neutrons, so they behave the same way chemically as the isotopes that occur in cells
63
Which subatomic particle is found in the nucleus of a hydrogen atom?
A proton only (no neutrons, and only one electron)
64
The atomic weight of an atom is its mass relative to what?
hydrogen. The atomic mass of an atom or molecule is specified in daltons, one dalton is equal to the mass of a hydrogen atom.
65
On the basis of mass, what type of molecule is the most abundant in a living bacterial cell?
Water. All cells are about 70% water by weight
66
Covalent bonds are formed by the sharing of electrons. In the cell, how are covalent bonds broken?
Enzyme catalysis that is specific for a protein and its substrate
67
Which of the following would most likely interact by forming an ionic bond?
ATP and magnesium cations (ATP is negatively charged)
68
How do protein, nucleic acid, and polysaccharide molecules polymerize (grow in length)
By condensation reactions. A molecule of water is lost with the addition of each monomer to to the growing polymer chain.
69

Cell Biology (24 decks)

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