Topic 2: chemical level of organization

Question 1

what does a nucleus contain?

Answer 1

-protons
-neutrons

Question 2

what orbits the nucleus?

Answer 2

-electrons

Question 3

are atoms electrically neutral?

Answer 3

-yes
-they have an equal number of protons and electrons
-neutrons may differ (isotopes)

Question 4

what is an ion?

Answer 4

-an ion is created if an atom loses or gains an electron
-it gains a charge
-negative ion - anion
-positive ion - cation

Question 5

what are important ions (electrolytes)?

Answer 5

-calcium
-sodium
-potassium
-hydrogen
-chloride

Question 6

what are electrolytes?

Answer 6

-substances that have a natural positive or negative charge when dissolved in water

Question 7

what is an ionic bond?

Answer 7

-the transfer of electrons
-positive and negative ions attract to form a bond
-ex: NaCl and KCl (salts)

Question 8

what is a covalent bond?

Answer 8

-the sharing of electrons between atoms
-ex: O2

Question 9

what is an organic substance?

Answer 9

• compounds made of covalently bonded carbon atoms
  -ex: carbohydrates, proteins, lipids, and nucleic acids

Question 10

what is an inorganic substance?

Answer 10

-lacking in carbon atoms
-ex: water, salts (NaCl), gases (O2)

Question 11

what are some inorganic compounds that are exceptions to the lack of carbon?

Answer 11

-carbonic acid (H2CO3)
-bicarbonate (HCO3-)
-carbon dioxide (CO2)
-carbon monoxide (CO)

Question 12

what is the most abundant substance in cells?

Answer 12

-water

Question 13

what does it mean when we say water is a polar molecule?

Answer 13

-there is an unequal sharing of electrons
-this leads to a slight charge difference
-oxygen is more electronegative so it will have a stronger pull on electrons

Question 14

why do many reactions in the body take place in water? what does this mean?

Answer 14

-water is a universal solvent
-this means that it can dissolve more substances than any other liquid

Question 15

what type of mechanism is water? what are two examples of what it maintains?

Answer 15

-transport mechanism
-transports chemicals, ex: O2, nutrients
-body temp and blood flow

Question 16

are acids and bases organic or inorganic?

Answer 16

-they can be both!
-ex: citric acid is organic

Question 17

what are acids?

Answer 17

-they are substances that increase the hydrogen concentration of a solution
-high [H+] = low pH (acidic)
-they disassociate in water to release H+ ions
ex: HCl (hydrochloric acid) in water (dissociates into H+ ions)

Question 18

what are bases?

Answer 18

-substances that reduce the hydrogen concentration of a solution
-low [H+] = high pH (basic)
-they dissociate in water to release OH- ions which then bind with free H+ ions
-ex: NaOH in water (Na+ + OH-)
-ex: HCO3 + H+ (H2CO3 > H2O + CO2)

Question 19

what is the pH scale?

Answer 19

-a measure of the [H+] of free H+ in a solution
- 0=basic > 7=neutral > 14=acidic
-ex: blood pH is around 7.35-7.45
-ex: OH- + H+ > H2O (neutralization)

Question 20

what are the important organic substances?

Answer 20

-carbohydrates
-lipids
-nucleic acids
-proteins
-ATP

Question 21

what are carbohydrates and what are their functions?

Answer 21

-consist of C, H, O
-common formula is (CH2O)n (n = #)
-source of energy for cells (glucose - C6H1206)
-used in cellular structures (DNA + RNA)

Question 22

monosaccharides

Answer 22

-simple sugars
-monomers of other more complex carbohydrates
-ex : glucose, fructose, ribose, deoxyribose

Question 23

disaccharides

Answer 23

-2 monosaccharides that are covalently bonded together
-ex :glucose + fructose = sucrose

Question 24

polysaccharides

Answer 24

-many monosaccharides bonded together
-ex: glycogen (animals) , starch (plants) (very similar in structure)

Question 25

what are lipids and what are their functions?

Answer 25

-consist of C, H , O (in a ratio that is different from carbs)
-they are insoluble (non-polar) in water
-they protect organs, build cell membranes, and are a source of stored energy

Question 26

between carbohydrates and lipids, which is a long term and which is a short term source of energy?

Answer 26

-carbohydrates are a short term source
-lipids are a long term source

Question 27

what are the types of lipids?

Answer 27

-glycerides
-phospholipids
-cholesterol
-steroids

Question 28

glycerides

Answer 28

-the most common lipid in our bodies and diet
-composed of 2 building blocks
-glycerol backbone and fatty acids
-different prefix naming based on the number of fatty acid tails
-mono, di, tri (ex: monoglyceride)

Question 29

phospholipids

Answer 29

-made of 3 building blocks
-phosphate head group (polar, hydrophillic)
-glycerol backbone
-2 fatty acid tails (non-polar, hydrophobic)
-basically a diglyceride with a phosphate head group

Question 30

Cholesterol

Answer 30

-found in cell membranes
-used to synthesize steroids
-made of a hydrocarbon tail and 4 fused rings with a hydroxyl group

Question 31

steroids

Answer 31

-derived from cholesterol
-ex: bile salts, vitamin d, hormones (testosterone + estrogen)

Question 32

what are proteins and what are their main functions

Answer 32

-they consist of C, H, O, N (sometimes S (albumin))
-one or more polypeptides that are folded into a specific shape
-they can be structural materials (collagen)
-enzymes, hormones, or transporters
-antibodies
-source of energy when carbs and lipids are in low supply (albumin (most abundant))

Question 33

what are amino acids

Answer 33

-basic building blocks of all proteins
-ex:glycine
-2 amino acids are called dipeptides
-many amino acids are called polypeptides

Question 34

what are nucleic acids?

Answer 34

-consist of C, H, O, N, P
-there are 2 forms
-DNA + RNA
-building blocks are called nucleotides

Question 35

what are nucleotides?

Answer 35

-the building blocks of nucleic acids
-contain a phosphate, monosaccharide (ribose in RNA and deoxyribose in DNA), and an organic nitrogenous base
-bases are Adenine, Thymine, Uracil, Cytosine, and Guanine

Question 36

which two organic nitrogenous bases are only present in certain nucleic acids?

Answer 36

-Thymine (DNA only)
-Uracil (RNA only)

Question 37

what is the structure and function of DNA?

Answer 37

-double stranded
-phosphate, deoxyribose, base (A, T, C, or G)
-bases bind together to form a double helix (A to T and G to C)
-sugars and phosphates alternate to form the sides of the ladder
-bases form the rungs of the ladder
-used for cellular reproduction
-used as a template to make RNA

Question 38

what is the structure and function of RNA?

Answer 38

-single stranded
-phosphate, ribose, base (A, U, C, or G)
-base pairs are, A to U and G to C
-used for protein synthesis

Question 39

what is ATP and what are its uses?

Answer 39

-adenosine triphosphate
-the energy stored in covalent bonds
-made of 3 phosphates + adenosine (ribose + adenine)
-powers cellular activities
-breaking bonds creates immediately useable energy (high energy bonds)
-when it breaks, it forms ADP (adenosine diphosphate) + Pi (inorganic phosphate)

Question 40

what is the reason why certain carbon containing molecules are exceptions to the inorganic molecules?

Answer 40

-they do not contain C-C bonds (carbons are not covalently bonded TOGETHER)

Question 41

why are acids and bases important?

Answer 41

-they play a critical role in maintaining the pH balance of cells, organs, and blood within narrow ranges

Question 42

what is ATP considered?

Answer 42

-a modified RNA nucleotide