Biochem topics

Question 1

LIFE:

Answer 1

A living thing is essentially a “bag of chemicals” (a cell).

Question 2

CARBON:

Answer 2

Carbon has 4 binding sites, meaning it can bond with 4 other elements. If 4 different elements bind to a single carbon atom, they can form different arrangements called isomers.

Question 3

Isomer:

Answer 3

Molecules with the same composition but arranged differently (e.g., D and L forms).

Question 4

Enzymes:

Answer 4

Molecules that perform work in living things, but only work with specific isomers.

Question 5

HYDROGEN:

Answer 5

A key element associated with hydrogen bonds, which influence molecular shape and structure. Hydrogen is abundant in the universe as a gas.

Question 6

OXYGEN:

Answer 6

A highly reactive element that bonds easily, including with other oxygen atoms.

Question 7

HYDROCARBONS:

Answer 7

The simplest molecules, composed of carbon and hydrogen.

Question 8

ALCOHOLS:

Answer 8

Molecules containing a hydroxyl group (-OH). The hydrocarbon part (R) determines the type of alcohol (e.g., ethanol, propanol, butanol).

Question 9

ALDEHYDES:

Answer 9

Molecules with a carbonyl group bonded to a hydrogen. Many sugars, such as glucose, are aldehydes.

Question 10

KETONES:

Answer 10

Molecules with a carbonyl group bonded to two R groups, without a hydrogen.

Question 11

ESTERS:

Answer 11

Molecules formed by reacting an alcohol with an acid. Many food smells come from esters.

Question 12

ETHERS:

Answer 12

Molecules with an oxygen atom bonded to two R groups. Ethers are vital for lipids, which are essential for cells.

Question 13

CARBOXYLIC ACIDS:

Answer 13

Contain a carboxyl group made of a carbonyl and hydroxyl group. These acids are involved in many biological molecules and interactions.

Question 14

ANHYDRIDES:

Answer 14

High-energy molecules like pyrophosphate. The prefix “pyro-“ means fire or energy. ATP is the most important anhydride.

Question 15

NITROGEN:

Answer 15

Found in amino groups (-NH₂), nitrates (NO₃⁻), nitrites (NO₂⁻), and nitrogen gas (N₂), which makes up 80% of the atmosphere.

Question 16

AMINO ACIDS:

Answer 16

The building blocks of proteins, with a carboxyl group, an amino group, and a variable R group. There are about 20 amino acids, and the L-isomers are predominant in living organisms.

Question 17

SULFUR:

Answer 17

Rare in biological molecules but important when present, such as in sulfhydryl groups (-SH). Sulfur is found in amino acids like cysteine and methionine.

Question 18

PHOSPHORUS:

Answer 18

Commonly found as phosphoric acid in DNA, RNA, and phospholipids. It’s a critical component of ATP, which provides energy.

Question 19

CARBOHYDRATES:
Monosaccharides:

Answer 19

The simplest carbohydrates, with 3–7 carbon atoms (e.g., glucose).

Question 20

Disaccharides:

Answer 20

Two monosaccharides joined together (e.g., lactose, sucrose, maltose).

Question 21

Polysaccharides:

Answer 21

Long chains of monosaccharides used in cell walls and energy storage (e.g., starch, pectin, cellulose).

Question 22

LIPIDS:
Fatty Acids:

Answer 22

Hydrocarbon chains with a carboxylic group.

Question 23

Triglycerides:

Answer 23

Composed of glycerol and three fatty acids.

Question 24

Phospholipids:

Answer 24

Lipids with hydrophilic heads and hydrophobic tails, forming bilayers in cell membranes.

Question 25

Waxes:

Answer 25

Lipids with very long hydrocarbon chains.

Question 26

NUCLEIC ACIDS:

Answer 26

Found in cells and viruses; include DNA and RNA.

Question 27

Nucleoside:

Answer 27

A molecule made of a pentose sugar and a purine or pyrimidine.

Question 28

Nucleotide:

Answer 28

A nucleoside with an added phosphate group.

Question 29

DEOXYRIBONUCLEIC ACID (DNA): Primary Structure:

Answer 29

The sequence of bases (~1,000 bases make up a gene).

Question 30

Secondary Structure:

Answer 30

Double-stranded, with complementary base pairing (A-T, G-C).

Question 31

Helix:

Answer 31

A double-stranded structure twisted into a helix (beta DNA).

Question 32

Major Groove:

Answer 32

A larger groove where proteins may bind.

Question 33

Minor Groove:

Answer 33

A smaller groove in the helix, also accessible to certain molecules but less commonly targeted than the major groove.

Question 34

Z-DNA:

Answer 34

A zigzag form observed using X-ray diffraction.

Question 35

RIBONUCLEIC ACID (RNA):

Answer 35

The product of transcription from DNA.

Question 36

Primary Structure:

Answer 36

The linear base sequence.

Question 37

Secondary Structure:

Answer 37

The 2D folding of RNA.

Question 38

Tertiary Structure:

Answer 38

The 3D folding of RNA.

Question 39

PROTEINS:

Answer 39

Made of amino acids linked by peptide bonds.

Question 40

PROTEIN STRUCTURE: Primary:

Answer 40

The sequence of amino acids.

Question 41

Secondary:

Answer 41

Folding due to hydrogen bonds.

Question 42

Tertiary:

Answer 42

Complex 3D folding caused by interactions like disulfide bonds.

Question 43

Quaternary:

Answer 43

The combination of multiple polypeptide chains into a functional protein.

Question 44

ENZYMES:

Answer 44

Globular proteins that act as biological catalysts.

Question 45

Active Site:

Answer 45

The specific area where the substrate binds.

Question 46

Cofactors:

Answer 46

Molecules that help enzymes function.

Question 47

Apoenzyme:

Answer 47

The protein part of the enzyme.

Question 48

Holoenzyme:

Answer 48

The enzyme with its cofactor.

Question 49

Classification:

Answer 49

Enzymes are grouped by their functions, including oxidoreductases, transferases, hydrolases, lyases, isomerases, and ligases.

Question 50

ENVIRONMENTAL FACTORS:

Answer 50

Enzymes work best at temperatures of 40–50°C and a pH of 7–8. High temperatures or extreme pH can denature enzymes.

Question 51

INHIBITORS: Competitive:

Answer 51

Chemicals that resemble the substrate and bind to the active site. Reversible. BABY EATS CARROTS, M&M COME, BABY EATS M&M. TAKE AWAY M&M, BABY EATS CARROTS

Question 52

Noncompetitive:

Answer 52

Bind to a different site on the enzyme and alter its shape. Reversible. BABY EATS CARROTS, SIBLING COME, POKES BABY. BABY STOP EATING AND STARTS FIGHTING

Question 53

ALLOSTERIC PROTEINS:

Answer 53

Enzymes with additional regulatory sites that can increase or decrease activity.

Question 54

Positive Effector:

Answer 54

Increases enzyme activity.

Question 55

Negative Effector:

Answer 55

Decreases enzyme activity.