Topic 2: chemical level of organization Flashcards
what does a nucleus contain?
-protons
-neutrons
what orbits the nucleus?
-electrons
are atoms electrically neutral?
-yes
-they have an equal number of protons and electrons
-neutrons may differ (isotopes)
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
what are important ions (electrolytes)?
-calcium
-sodium
-potassium
-hydrogen
-chloride
what are electrolytes?
-substances that have a natural positive or negative charge when dissolved in water
what is an ionic bond?
-the transfer of electrons
-positive and negative ions attract to form a bond
-ex: NaCl and KCl (salts)
what is a covalent bond?
-the sharing of electrons between atoms
-ex: O2
what is an organic substance?
- compounds made of covalently bonded carbon atoms
-ex: carbohydrates, proteins, lipids, and nucleic acids
what is an inorganic substance?
-lacking in carbon atoms
-ex: water, salts (NaCl), gases (O2)
what are some inorganic compounds that are exceptions to the lack of carbon?
-carbonic acid (H2CO3)
-bicarbonate (HCO3-)
-carbon dioxide (CO2)
-carbon monoxide (CO)
what is the most abundant substance in cells?
-water
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
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
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
are acids and bases organic or inorganic?
-they can be both!
-ex: citric acid is organic
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
