Chemistry Of Life

Question 1

Four main classes of macromolecules present in cells

Answer 1

1. Carbohydrates (made of sugars)
2. Proteins (made of amino acids)
3. Nucleic acids (made of nucleotides)
4. Lipids (fats, phospholipids, and steroids)

Question 2

Carbohydrates are composed of ____ and can be classified into (4)

Answer 2

-composed of C, H, and O
Classified into:
-Fibre
-Starch
-Polysaccharide (complex sugars)
-Monosaccharides (simple sugars)

Question 3

Glycogen is

Answer 3

A polysaccharide used for storage in animal cells that can be catabolized through Glycogenolysis to yield energy

Question 4

Proteins are made of

Answer 4

Amino acids

Question 5

Enzymes are

Answer 5

Proteins that catalyze reactions in all living cells

Question 6

Essential functions of Proteins (5)

Answer 6

-Catalysis (enzymes)
-Signalling
-Structure of cell
-Transport
-Energy/Gradient Generation

Question 7

Nonessential amino acids can

Answer 7

Be synthesized by the organism

Question 8

Essential amino acids

Answer 8

MUST be in the diet, the organism cannot synthesize (make it) on its own

Question 9

In a dehydration reaction (2)

Answer 9

-H2O is produced
-a peptide bond is formed between the carbon and nitrogen

Question 10

A polypeptide chain is a

Answer 10

Linear sequence of amino acids connected by a peptide bond

Question 11

What is the basic structure of an amino acid (3)

Answer 11

-a Carboxyl group (COOH)
-an amino group (NH3)
-a side chain (R group)

Question 12

Transcription is

Answer 12

DNA making RNA

Question 13

Translation is

Answer 13

RNA making proteins

Question 14

What are the two Nucleic Acids

Answer 14

-Deoxyribonucleic Acid (DNA)
-Ribonucleic Acid (RNA)

Question 15

Nitrogenous Bases of DNA vs RNA

Answer 15

DNA:
-Adenine
-Thymine
-Guanine
-Cytosine

RNA:
-Adenine
-Uracil
-Guanine
-Cytosine

Question 16

Lipids are ___ and include (3)

Answer 16

-poorly soluble in water
-Fats
-Phospholipids
-Steroids

Question 17

Three functions of Lipids

Answer 17

-crucial part of cell membranes
-cell signalling
-energy storage

Question 18

Lipids are often found as ___, which consists of ____

Answer 18

-Triglycerides
-glycerol backbone and 3 fatty acid molecules

Question 19

A Lipid in a solid state is called ___ while a Lipid in a liquid state is called ___

Answer 19

Fats; Oils

Question 20

Saturated fats are

Answer 20

Fatty acids that have only single bonds between their C atoms

Question 21

Unsaturated fats

Answer 21

Have some double bonds in their hydrocarbon chain

Question 22

Phospholipids (5)

Answer 22

-make up all animal cell membranes
-have 2 fatty acid chains bound to a glycerol backbone
-have a phosphate group bound to the third C
-Hydrophilic head (water soluble)
-Hydrophobic tail (insoluble)

Question 23

Cholesterol (4)

Answer 23

-made in the liver
-poorly absorbed in the diet
-influences membrane fluidity
-precursor of ALL steroids (including hormones)

Question 24

Anabolism (3)

Answer 24

-energy stored in cells
-used to help build / repair structures
-small to large molecules

Question 25

Catabolism (2)

Answer 25

-breakdown of body tissues (ie. large to small molecules) -used to create energy

Question 26

The by-product of Metabolism is ___ which is used for (2)

Answer 26

-Heat -Thermoregulation and Maintaining Homeostasis

Question 27

Endergonic reactions

Answer 27

Absorb free energy (anabolic)

Question 28

Exergonic reactions

Answer 28

Release energy (catabolic)

Question 29

Activation energy is the

Answer 29

Initial energy investment required to reach UNSTABLE transition state

Question 30

The Transition State is when

Answer 30

Molecules absorb energy and become unstable, thus allowing their bonds to be broken

Question 31

Enzymes lower ___ by ____

Answer 31

-Activation Energy -binding to its substrate(s) forming a complex

Question 32

Two types of enzyme inhibitors are

Answer 32

-competitive (bind reversibly to an enzyme) -non-competitive (do not bind to the active site)

Question 33

Feedback inhibition is one of the

Answer 33

Most common way to regulate a metabolic path

Question 34

Cellular Respiration (3)

Answer 34

-breaks down the molecular components in food -produces H2O and CO2 -generates ATP

Question 35

3 stages of Cellular Respiration

Answer 35

1. Glycolysis 2. Krebs Cycle 3. Electron Transport Chain and Oxidative Phosphorylation

Question 36

Oxidation (2) and an example

Answer 36

-loss of electrons -losing/sharing electrons to/with oxygen -glucose is oxidized to form CO2

Question 37

Reduction (2) and an example

Answer 37

-gaining of electrons -gaining/sharing electrons from/with Hydrogen -oxygen is reduced to form water

Question 38

Glycolysis (4)

Answer 38

-first step in Cellular Respiration -takes place in cytoplasm -does NOT require oxygen (anaerobic) -splitting of glucose into 2 Pyruvic Acids

Question 39

During cellular respiration, pyruvate is diffused to ____ where ____ occurs

Answer 39

-the mitochondria -Krebs Cycle and ETC

Question 40

During the Krebs Cycle ___ is converted to ____

Answer 40

Pyruvate; Acetyl-CoA

Question 41

Enzyme that catalyses the conversion of pyruvate to Acetyl-CoA

Answer 41

Pyruvate Dehydrogenase

Question 42

Pyruvate Dehydrogenase (PDH) is controlled by (2)

Answer 42

-Pyruvate Dehydrogenase Kinase (PDK): makes PDH inactive -Pyruvate Dehydrogenase Phosphatase (PDP): reverses PDK

Question 43

Main product of the Krebs Cycle used in the Electron Transport Chain is

Answer 43

NADH

Question 44

One glucose molecule can produce

Answer 44

30-32 ATP

Question 45

Electron Transport Chain (5)

Answer 45

-occurs in the inner mitochondrial membrane -consists of four protein complexes labelled I to IV -electrons (NADH and FADH2) enter through complex I or II -proton gradient is created within the intermembrane space -complex IV produces water

Question 46

The major role of the ETC is (2)

Answer 46

-pump H+ from the matrix into the intermembrane space -ATP Synthase moves H+ back across the membrane creating ATP

Question 47

Chemiosmosis is

Answer 47

Using an H+ gradient to do work

Question 48

What is the effect of strenuous exercise on the ETC (4)

Answer 48

-increase in body temperature -decrease in pH creates an acidosis -this increase in acid mainly occurs in Complex I, causing less H+ being generated -cuts ATP synthesis in half, causing fatigue

Question 49

Traditionally, anaerobic metabolism was thought

Answer 49

That a build up of Lactic Acid was not good and created Hypoxia

Question 50

The Lactate Shuttle (3):

Answer 50

-in the liver, lactate is converted to glucose via Glyconeogensis -in glycolysis skeletal muscle, glucose is used to produce lactate which goes to oxidative skeletal muscle -in oxidative skeletal muscle, lactate is converted back into pyruvate which can either go back to the liver and repeat the cycle OR be used in the Krebs Cycle