Chapter 1: Biochemistry and the Unity of Life

Question 1

List the 4 major biomolecules

Answer 1

Proteins, Nucleic acids, Lipids and Carbohydrates

Question 2

What is the central dogma of molecular biology?

Answer 2

DNA –> RNA –> Protein

Question 3

Proteins

Answer 3

+ Highly versatile
+ constructed from 20 a.a.
- signal molecules + receptors for signaling molecules
- play structural roles: muscle, membrane and cytoskeleton
- Most prominent role is being a catalyst

Question 4

Nucleic Acids

Answer 4

+store and transfer info
+linear molecules
-constructed from 4 nucleotides
-ATP
-informational biomolecules

Question 5

DNA - comp

Answer 5

4 deoxyribonucleotides possible (base variability)
- adenine, guanine, cytosine, thymine
-double-helix
-phosphodiester linkages

Question 6

RNA - comp

Answer 6

• single stranded
• contains additional OH group
  -uracil replaces thymine
  -mRNA copies DNA regions

Question 7

Lipids

Answer 7

+smaller than protein & nucleic acids
+ lighter molecular weights
+ not polymers
- Dual chemical nature (hydrophobic and hydrophilic)
- barrier formation
-also store energy
-signaling molecule

hydrophobic component can undergo combustion to provide Energy

Question 8

Carbohydrates

Answer 8

-important fuel source
- glucose is most common
- Role in cell signaling and cell recognition
+ carbs are linked together in highly branched chains (important for cell-cell comms.)

Question 9

Glucose in plants vs animals

Answer 9

Plant - starch
Animal - glycogen

Question 10

DNA replication steps

Answer 10

1. replication:
   DNA copied - catalyzed by DNA polymerase
2. transcription
   copied genes are made accessible - DNA –> RNA, catalyzed by RNA polymerase
   3.translation:
   info encoded in mRNA is realized - nucleic acid –> protein
   - occurs on ribosomes

Question 11

Eukaryote

Answer 11

contain membrane-enclosed compartments

Question 12

Prokaryote

Answer 12

simple structure
-2 membranes separates by periplasmic space

Question 13

Microbiome

Answer 13

collection of organisms that live in a particular environment

Question 14

Human microbiome

Answer 14

all microorganisms living in + on the human body

Question 15

Microbiome disruption may cause development of….

Answer 15

Type II diabetes
Cardiovascular disease
Liver disease
Inflammatory bowel disease

Question 16

Cell membrane

Answer 16

a lipid bilayer organized with chains and heads that separate environments
impermeable to most substances (fuels, signal molecules and building blocks)

Question 17

Selective permeability

Answer 17

achieved by embedded proteins - facilitate entry of glucose, a.a. and info transduction

Question 18

Cytoplasm

Answer 18

Site of many biochemical processes:
1. initial stage of glucose metabolism
2. fatty acid synthesis
3. protein synthesis

Question 19

Cytoskeleton

Answer 19

network of structural filaments - 3 protein fibers:
1.actin filaments
2.intermediate filaments
3. microtubules
all support cell structure, localize biochemical activities + serve as molecular highways

Question 20

Nucleus

Answer 20

• double-membrane bounded organelle
• info center - location of genome
  + porous membrane for transport
  + where molecular machines function
  + where genomic info is selectively expressed

Question 21

Mitochondrion

Answer 21

+outer membrane touches cytoplasm
-inner membrane defines the matrix
+fuel molecules undergo combustion into CO2+H2O+ATP
+90% of Energy used by cell comes from

• energy production

Question 22

Endoplasmic reticulum

Answer 22

+ series of membranous sacs where reaction take place (on cytoplasmic surface + lumens)
- Smooth ER –> processing exogenous chemicals
- rough ER: ribosomes produce membrane or secretory proteins
+Rough ER –> ribosomes synthesize proteins + translation in ER lumen + protein folding with chaperones + protein bud off RER as transport vesicles

Question 23

Golgi complex

Answer 23

• Process proteins from RER
  +transport vesicles from RER come to Golgi
  +further procession occurs (glycosylation)
  +Golgi sorts protein by function + future place

Question 24

Exocytosis

Answer 24

secretory granules bud off Golgi and fuse with cell membrane for release/secretion of biomolecules

Question 25

Endocytosis

Answer 25

entry of biomolecules (Fe, Vit B12, Cholesterol) into the cell
large molecules = phagocytosis

Question 26

Endosome

Answer 26

Plasma membrane invaginates and buds off into cell

Question 27

Lysosomes

Answer 27

-Formed by Golgi ->formation similar to secretory granules
-fuse with endosomes to digest ingested contents (degradation)
- also digest damaged intracellular organelles

Question 28

Familial hypercholesterolemia

Answer 28

-can cause heart attacks is 6 yr olds
-poor endocytosis of cholesterol from the blood

Question 29

Tay-Sachs disease

Answer 29

-destructive for neurons
-cause muscle weakness, dementia and death at an early age
-failure of lysosomes to function properly
buildup of sphingolipids

Question 30

The biochemicals that make up 98% of humans

Answer 30

Hydrogen, Oxygen and Carbon

Question 31

The biochemical that follow after the main 3

Answer 31

Nitrogen, phosphorus and sulfur

Question 32

Silicon is more abundant than carbon but why is it not vital?

Answer 32

Si-Si bonds are weaker than C-C bonds
- C-C bonds used for strong backbones
- More Energy released from breaking C-C bonds
- oxidized silicon is insoluble in water