Topic 2: chemical level of organization Flashcards by Zenah Large

what does a nucleus contain?

-protons
-neutrons

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what orbits the nucleus?

-electrons

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are atoms electrically neutral?

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

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what is an ion?

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

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what are important ions (electrolytes)?

-calcium
-sodium
-potassium
-hydrogen
-chloride

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what are electrolytes?

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

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what is an ionic bond?

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

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what is a covalent bond?

-the sharing of electrons between atoms
-ex: O2

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what is an organic substance?

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

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what is an inorganic substance?

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

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

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

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what is the most abundant substance in cells?

-water

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

-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

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

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

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

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

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are acids and bases organic or inorganic?

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

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what are acids?

-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)

what are bases?

-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)

what is the pH scale?

-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)

what are the important organic substances?

-carbohydrates
-lipids
-nucleic acids
-proteins
-ATP

what are carbohydrates and what are their functions?

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

monosaccharides

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

disaccharides

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

polysaccharides

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

what are lipids and what are their functions?

-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

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

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

what are the types of lipids?

-glycerides -phospholipids -cholesterol -steroids

glycerides

-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)

phospholipids

-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

Cholesterol

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

steroids

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

what are proteins and what are their main functions

-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))

what are amino acids

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

what are nucleic acids?

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

what are nucleotides?

-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

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

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

what is the structure and function of DNA?

-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

what is the structure and function of RNA?

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

what is ATP and what are its uses?

-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)

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

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

why are acids and bases important?

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

what is ATP considered?

-a modified RNA nucleotide