chapter 2

Question 1

four major classes of biomolecules

Answer 1

proteins
carbohydrates
lipids
nucleic acids

Question 2

biomolecules primarily consist of four different atoms

Answer 2

CHON

Question 3

two main types of proteins

Answer 3

1. structural: form structural components of the cell
2. enzymes: speed and regulate biochemistry

Question 4

what causes a protein to fold?

Answer 4

occurs spontaneously, based on amino acid sequence ; environmental factors also affect conformation

Question 5

four levels of protein structure

Answer 5

primary
secondary
tertiary
quaternary

Question 6

carbohydrates

Answer 6

• sugars and sugar polymers
• mono and poly
• function: energy and structure

Question 7

lipids

Answer 7

• molecules that are mostly H and C
• functions: energy source, structural, cholesterol

Question 8

function of nucleic acids

Answer 8

information storage
energy source

Question 9

central dogma

Answer 9

dna - rna - protein

Question 10

dna organization

Answer 10

organized into distinct units called chromosomes

Question 11

chromatin (large)

Answer 11

• all genetic material in nucleus
• 3 x 109 base pairs

Question 12

chromosome (medium)

Answer 12

• dna/protein structures carrying genes
• 1 x 106/7 nucleotides per chromosome
• 23 pairs in humans

Question 13

gene (small)

Answer 13

• nucleotide sequence of dna that controls one hereditary characteristic of an organism
  -encodes an rna molecule

Question 14

heterochromatin

Answer 14

tightly packed chromatin, not available for gene expression

Question 15

cell membrane

Answer 15

• barrier to maintain the cell’s internal chemistry
• phospholipids and diverse proteins

Question 16

mitochrondria

Answer 16

use sugar, fat and protein to make atp

Question 17

ER and golgi

Answer 17

allow for the manufacture and secretion of biomolecules

Question 18

cytoskeleton

Answer 18

gives shape and support

Question 19

intercellular materials

Answer 19

1. amorphous: vary in their H2O/protein content
2. fibers: collagen and elastin

Question 20

why do cells divide?

Answer 20

1. growth/development
2. repair/regeneration
3. reproduction

Question 21

cells reproduce via mitosis

Answer 21

1. chromosomes are duplicated by dna replication
2. pulled apart by the cytoskeleton, which pinches cell in half

Question 22

do all cells divide?

Answer 22

frequency of mitosis depends on cell type : continous, based on need, and rare/never

Question 23

evolution

Answer 23

• the change in genetic composition of a population from generation to generation, that over time brings about new species
• occurs by mutation
• proceeds by natural selection

Question 24

three criteria for valid theory

Answer 24

1. changes addressed must occur commonly in all members of species
2. process must be progressive
3. process must lead to organ dysfunctions that ultimately lead to failure of organ

Question 25

three main groups of theories

Answer 25

1. aging results from wearing out of organ 2. aging results from nonreversible chemical changes within cells that alter its functioning 3. aging is programmed by a biological clock, located in center of each cell

Question 26

theories of aging

Answer 26

genetic rate of living free radical mitochondrial clinker cross linkage immune deficiency wear and tear

Question 27

genetic theories

Answer 27

death gene telomere somatic mutation faulty dna repair error catastrophe

Question 28

death gene theory

Answer 28

a set of genes activates late in life, and tells the body to deteriorate and die

Question 29

telomere theory

Answer 29

shortening of telomeres affects the expression of certain genes

Question 30

somatic mutation theory

Answer 30

harmful factors may injure genes (radiation)

Question 31

faulty dna repair theory

Answer 31

dna damage is repaired early in life, overtime repair mechanisms begin to fail

Question 32

error catastrophe (disproven)

Answer 32

damage to rna and protein result in biological aging

Question 33

rate of living theory (disproven)

Answer 33

metabolic rate is directly related to the rate of aging, and inversely related to life span

Question 34

free radical theory

Answer 34

an atom/molecule with an odd number of e-s-an unpaired electron - highly reactive, occur naturally, eliminated by antioxidants

Question 35

mitochondrial theory

Answer 35

mitochondrial activity and damage cause aging

Question 36

clinker theory

Answer 36

waste products accumulate in cells over time

Question 37

cross linkage theory

Answer 37

post-translational modification to proteins resulting in irreversible changes to their structure, occurring over time. affects flexibility and functioning - due to free radicals and glucose

Question 38

glycation

Answer 38

covalent joining of a sugar to a protein via particular amino acids

Question 39

immune deficiency theory

Answer 39

over time, immune system begins to damage your tissues (autoimmunity)

Question 40

wear and tear theory

Answer 40

an accumulation of injuries adversely affects the tissues/bodies