3 Chem of life (35/35) Flashcards

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1
Q

3.1.1 Sate that the most frequently occurring chemical elements in living things are ______, _____, _____ and ______.

A

the most frequently occurring chemical elements in living things are carbon, hydrogen, oxygen and nitrogen.

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2
Q

3.1.2 Sate thata variety of other elements are needed by living organisms, including _____, _______, _______, _____ and ______.

A

a variety of other elements are needed by living organisms, including sulfur, calcium, phosphorus, iron and sodium.

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3
Q

3.1.3 Sate one role for each of the elements mentioned in 3.1.2.

A

sulfur: Prokaryotes(chemical rxn involving sulfur as source of E), Plants+Animals(required to produce some of the amino acids that are part of enzymes they need)
phosphorus: Prokaryotes+Plants+Animals(all contain ATP and DNA, which contain phophorus)
calcium: Prokaryotes(maintaining cell structure and movement), Plants(component of cell walls and membranes), Animals(make out bones hard, lack causes osteoporosis, plays a role in releasing the neurotransmitter in the synapse when nerve messages are being transmitted)
iron: Prokaryotes(some anaerobic bacteria use a chemical rxn involving iron as their source of E), Plants(needed to hep the formation of chlorophyll), Animals(component of hemoglobin found in red blood cells; hemoglobin helps oxygen transport)
sodium: Prokaryotes(indirectly helps move the flagellum), Plants(in some plants sodium can help bind CO2 for photosynthesis), Animals(creating an action potential in neurons and aids glucose transport across membranes)

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4
Q

3.1.4 Draw and label water molecules to show their polarity and hydrogen bond formation.

A
do so
    O -
 /       \ 
H       H + ~~ O -
                     /    \
                  H      H
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5
Q

3.1.5 Outline the thermal, cohesive and solvent properties of water.

A

thermal:
- high specific heat capacity: water requires a lot of energy to warm up and gives off a lot of energy when cooled down
-high heat of vaporization: water requires a lot of energy to change from a liquid to a gas
cohesive:
- the attraction forces between molecules of the same kind, strong in water molecules due
to H-bonds
solvent:
-water is polar and will dissolve many polar solutes “like dissolves like”

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6
Q

3.1.6 Explain the relationship between the properties of water and its uses in living organisms as a coolant, medium for metabolic reactions and transport medium.

A

thermal:
-use: transport: blood can carry heat to cooler regions
-use: coolant: plants/animals evaporate water which has a cooling effect - a little water will take lots of E to evaporate
cohesive:
-use: transport of water up the xylem of plants
solvent:
-use: transport in plants/animals is easier when molecules are dissolves, liquids are easier to transport: blood, xylem
-use: medium for metabolic rxns

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7
Q

3.2.1 Distinguish between organic and inorganic compounds.

A

Organic: are produced by living things and include all compounds containing CARBON (except: hydro carbonates, carbonates, oxides of carbon (CO, CO2)
Inorganic: all other compounds

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8
Q

3.2.2 Identify amino acids, glucose, ribose and fatty acids from diagrams showing their structure.

A

aa: central C atom, attatched to C: anmine group (NH2), carboxyll group (COOH), H group, R group(differs)
polypeptides: many aa, bonded together by peptide bonds
glucose: 6 carbons
ribose: 5 carbons
fatty a:carboxylic group
1 or more double bonds = unsaturated
no double bonds = saturated

see structures in book

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9
Q

3.2.3 List three examples each of monosaccharides, disccharides and polysaccharides.

A
monosaccharides:
1. glucose 
2. fructose 
3. galactose
disccharides:
1. maltose
2. sucrose
3. lactose
polysaccharides:
1. starch 
2. glycogen 
3. cellulose
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10
Q

3.2.4 Sate one function of glucose, lactose and glycogen in animals, and of fructose, sucrose and cellulose in plants.

A

Animals:
-glucose:source of E (respiration–>ATP)
-lactose: sugar found in milk, provide a source of E for babies
-glycogen: short term E storage in liver
Plants:
-fructose: sweet, good source of E
-sucrose: transport and storage of E
-cellulose: fibres, arranged in layers provide strength to cell wall

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11
Q

3.2.5 Outline the role of condensation and hydrolysis in the relationships between monosaccharides, disaccharides and polysaccharides; between fatty acids, glycerol and triglycerides; between amino acids and polypeptides.

A

Condensation: make complex
monosaccharide + monosaccharide –> disaccharide + water
Many monosaccharides or disaccharides –> polysaccharide + water
ex: glucose + glucose –> maltose + water
ex: glycerol + 3 fatty acids –> triglyceride + 3 water
Hydrolysis: make simpler
disaccharide + water –> monosaccharide +monosaccharide
polysaccharide + water –> Many monosaccharides or disaccharides
ex: sucrose + water –> glucose + fructose
ex: lactose + water –> glucose + galactose

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12
Q

3.2.6 Sate thee functions of lipids.

A
  1. energy storage
  2. thermal insulation
  3. main component of cell membrane (phospholipids)
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13
Q

3.2.7 Compare the use of carbohydrates and lipids in energy storage:

A
1g. lipid contains 2x as much E as 1g. carbohydrate (or protein) 
Lipids: 
-lipids needed for long term storage 
-light in weight (same amount of E in carbohydrates would weigh a lot more since more carbs would be needed) 
Carbohydrates: 
-short term energy storage between meals 
ANIMALS
-L:long term
-C:between meals
PLANTS
-L:immobile regions of plant (roots) 
-C:mobile, light weight (seeds)
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14
Q

3.3.1 Outline nucleotide structure in terms of sugar (deoxyribose), base and phosphate.

A

Deoxyribonucleic acid (DNA) is nucleic acid which is a long chain of molecules called nucleotides.
Nucleotides:
-pentose (5) sugar (deoxyribose)
-phosphate (H3PO4 forms 5 bonds with other atoms)
-organic base (nitrogen base: A, C, G or T)
~held together by covalent bonds

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15
Q

3.3.2 State the names of the four bases in DNA.

A

G - guanine
A - adenine
T - thymine
C - cytosine

EXTRA: 
PAIRS: ATU,  CG
ATU: form 2 H-bonds 
CG: form 3 H-bonds
AG: purines (big 2 ring structures) 
CTU: pyrimidines (small 1 ring structures)
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16
Q

3.3.3 Outline how DNA nucleotides are linked togethr by covalent bonds into a single strand.

A

nucleotides are formed using condensation rxns: phosphate + sugar + base –> nucleotide + 2 water
linked together to form a single chain by a condensation rxn between the phosphate of one nucleotide and the sugar of another
backbone: phos covalently bonded to sugar ([deoxy]ribose) , bases stick out (attached to sugar)

17
Q

3.3.4 Explain how a DNA double helix is formed using complementary base pairing and hydrogen bonds.

A

-nucleotide backbone (phosphate covalently
-bonded to pentose sugar(deoxyribose)
bases
-2 backbone strands run anti-parallel with nitrogen bases bonded in the middle
-to fill the middle space the organic bases have to combine to form 3 rings
-they need to form the same # of H-bonds
~A&T bond, C&G bond
-bonds between strands are H-bonds (weaker than covalent bonds)

18
Q

3.3.5 Draw and label a simple diagram of the molecular structure of DNA.

A

do that :P

http://www.contexo.info/DNA_Basics/images/nucleotideHGPweb.gif

19
Q

3.4.1 Explain DNA replication in terms of unwinding the double helix and separation of strands by helicase, followed by formation of the new complementary strands by DNA polymerase.

A
  1. DNA double helix unwinds/unzips: helicase
  2. free nucleotides in the nucleus form complementary base pairs w/ nucleotides on DNA
  3. DNA polymerase attaches the nucleotides to one another to create a new strand
  4. the old and the new strands join to form a new DNA helix
    (more detes in HL)
20
Q

3.4.2 Explain the significance of complimentary base paring in the conservation of the base sequence of DNA.

A

every organic base will only fit with one other base, the new DNA strand formed must be identical to the old strands complimentary strand.
replication can occur endlessly w/o change in DNA sequence theoretically
h/v mistakes called mutation occur

21
Q

3.4.3 Sate that DNA replication is ________________.

A

DNA replication is semiconservative.

22
Q

3.5.1 Compare the structure of RNA an DNA.

A

RNA:

  • Shape: usually single stranded
  • Sugar: ribose
  • Bases: A,> U
  • Shape: double helix (2 strands)
  • Sugar: deoxyribose
  • Bases: A,> T <, C, G
23
Q

3.5.2 Outline transcription in terms of the formation of an RNA strand complementary on the DNA strand by RNA polymerase.

A
  • Transcription: the process by which RNA is produced from DNA template
  • takes place in the nucleus, involves DNA strand that needs to unzip
  • 1 DNA strand(‘anti sense’) is transcribed –> 1 complimentary RNA strand made called mRNA/messenger RNA
  • mRNA is identical (same nucleotide sequence) to ‘sense strand’ except T–>U (Uracil)
  • after transcription mRNA leaves the nucleus through the nuclear pores in the nuclear membrane, into the cytoplasm
24
Q

3.5.3 Describe the genetic code in terms of codons composed of triplets of bases.

A

codon: 3 nucleotides (4^3 = 64 different codons)
20 a.a.s are found in cells (>1 codon can code for an a.a.)
sequence of nucleotides, determines the system of codons, which determines the a.a. sequence in the polypeptide, which determines the type of protein that the polypeptide forms.

mRNA codon table is used to determine which codon codes for which a.a.

25
Q

3.5.4 Explain the process of translation, leading o polypeptide formation.

A

Translation: the assembly of a polypeptide in a sequence specified by the order of nucleotides in the mRNA

  • in cytoplasm
  • ribosomes attach to the mRNA, covering area of 3 codons
  • tRNA carrying and a.a. will come in and the anti-codon exposed on the tRNA will have complimentary binding with the mRNA in the A site of the ribosome
  • tRNA will move to the P site
  • 2nd tRNA will so what 1st tRNA did, 2nd a.a. will attach to the 1st a.a
  • 1st tRNA will move to E site, 2nd tRNA will move to P site, 3rd tRNA will bind to A site , 1st tRNA will be released….so on forming a polypeptide
  • STOP codon, does not code for an a.a., terminates translation
26
Q

3.5.5 Discuss the relationship between one gene and one polypeptide.

A
  • a gene is a seq. of DNA that codes for a polypeptide seq., converted via transcription and translation(joining aa into polypep. chain according to codon seq.)
  • genetic code is universal=all organisms show the same relationship between genes and polypeptides
  • some proteins may consist of many polypeptide chains (thus need multiple genes)
  • gene mutation: synthesis of a defected polypeptide
27
Q

3.6.1 Define enzyme and activation site.

A

enzyme: a globular protein that increases the rate of a biological rxn by lowering the Ea (bio catalyst), remains unchanged
activation site: the site on the surface of the enzyme to which the substrate binds, it is specific

28
Q

3.6.2 Explain enzyme-substrate specificity.

A
  • active site & substrate compliment each other (shape/chemically)
  • active site + substrate = enzyme substrate complex
  • Lock and Key model
29
Q

3.6.3 Explain the effects of temperature, pH and substrate concentration of enzyme activity.

A

temperature: every enzyme has an optimum temperature where activity will peak, too high(or too low) temperatures will lead to denaturing, increasing temperature until the opt is reached increases activity due to KE/collision theory
pH: opt pH=highest activity
substrate concentration: increase=increase in enzyme activity, after a certain point, rate of rxn stabilizes b/c all activation sites are occupied

30
Q

3.6.4 Define denaturation.

A

denaturation: a structural change in a protein that results in a loss (usually permanent) of its biological properties.

31
Q

3.6.5 Explain the use of lactase in the production of lactose-free milk.

A

-Lactose is a disaccharide which can be broken down by the enzyme lactase (hydrolysis)
lactose + water -lactase-> galactose + glucose
-w/o lactose consumption, ability to digest lactose decreases
-lactase produced by yeast/bacteria
-attach lactase to a large molecule and let milk pass over it–> lactose free milk

uses of lactose free milk:

  • source of milk for lactose-intolerant
  • increase sweetness of milk, reducing the need for artificial sweeteners
  • reduces crystallization of ice cream
  • shortens production time for yogurt and cheese
32
Q

3.7.1 Define cell respiration.

A

cell respiration: the controlled release of energy from organic compounds in cells to form ATP

33
Q

3.7.2 Sate that, in cell respiration, _____ in the cytoplasm is broken down by ______ into _____, with a small yield of ___.

A

in cell respiration, glucose in the cytoplasm is broken down by glycolysis into pyruvate, with a small yield of ATP. (2 net)

34
Q

3.7.3 Explain that, during anaerobic respiration, pyruvate can be converted in the cytoplasm into lactate, or ethanol and carbon dioxide, with no further yield of ATP.

A

-anaerobic respiration: no oxygen
-to generate ATP from glycolysis, pyruvate must be converted into another form (to restore NAD levels for glycolysis)
-Conversion of pyruvate (in cytoplasm)
–ANIMALS: lactic acid (lactate)
–PLANTS: ethanol and CO2
reversible and levels can be restored when oxygen is present

35
Q

3.7.4 Explain that, during aerobic cell respiration, pyruvate can be broken down in the mitochondrion into carbon dioxide and water with a large yield of ATP.

A

aerobic respiration: oxygen present

  • in mitochondria (starts in cytoplasm[link rxn])
  • pyruvate is converted into CO2 and H2O, w/ large yield of ATP (net gain= 36 ATP)