Ch. 16- Biochemistry Flashcards
biochemistry
the study of the chemistry of living things and life processes
cell
structural unit of all living things
cell membrane
the double layer of lipid molecules enclosing a cell, through which the cell absorbs nutrients and eliminates waste
major parts of the cell & their functions
- nucleus: contains DNA molecules, which control heredity
- ribosomes: handles protein synthesis
- mitochondria: produces energy; the cell’s “batteries”
- (plant cells only) chloroplasts: convert energy from the sun to chemical energy
what are the main sources of energy for plant cells & for animal cells?
plant cells = the sun
animal cells = carbohydrates, fats, proteins
metabolism
the set of coordinated chemical reactions that keep the cells of an organism alive
catabolism
any metabolic process in which complex compounds are broken down into simpler substances
anabolism
the building up of molecules through metabolic processes
carbohydrate
a compound consisting of carbon, hydrogen, and oxygen, with hydrogen and oxygen in a 2:1 ratio; a starch or sugar
monosaccharide
a carbohydrate that cannot be hydrolyzed into simpler sugars
aldose
a monosaccharide with an aldehyde functional group (glucose & galactose)
ketose
a monosaccharide with a ketone functional group (fructose)
disaccharide
a sugar that on hydrolysis yields two monosaccharide molecules per molecule of disaccharide (sucrose & lactose)
which monosaccharides are yielded by hydrolyzing sucrose?
glucose & fructose
which monosaccharides are yielded by hydrolyzing lactose?
glucose & galactose
polysaccharide
a carbohydrate, such as starch or cellulose, that consists of many monosaccharide units linked together
alpha linkage (a-linkage)
the way glucose units are linked in starch; results in bent polymers with helix-like chains that form granules
beta linkage (b-linkage)
the way glucose units are linked in cellulose; results in long polymers with straight chains that form fibers
amylose
a plant starch that consists of glucose units joined in a continuous chain like beads on a string, resulting in long granules
amylopectin
a plant starch that consists of branched chains of glucose units; forms a branch about every 25 glucose units, resulting in long granules
glycogen
an animal starch that consists of branched chains of glucose units; forms a branch about every 10 glucose units, resulting in small granules/clusters
what are the dietary carbohydrates?
- sugars
2. starches
blood sugar
glucose, a simple sugar that is circulated in the bloodstream and used directly by cells for energy
how is high-fructose corn syrup (HFCS) made?
by treating corn syrup with enzymes to convert much of the glucose to fructose
how is corn syrup made?
by splitting long cornstarch chains
starch
a polymer of glucose units joined by alpha linkages; a complex carbohydrate
cellulose
a polymer comprised of glucose units joined by beta linkages
what does the human body do with glucose?
breaks it down through a complex set of over fifty chemical reactions that result in the production of carbon dioxide, water, and energy
what does the human body do with fructose?
stores it in the liver to stimulate the formation of fats
what does the human body do with cellulose?
it cannot break down/catabolize it; used as dietary fiber
what does the human body do with lactose?
every typical human is born with an enzyme that catabolizes lactose, but as some humans age, they begin lacking that enzyme, resulting in lactose intolerance
what does the human body do with starch?
hydrolyzes it to glucose
what happens when we eat more carbohydrates than our body can use?
the body stores the excess carbohydrates in the liver & in muscle tissue as glycogen
whats the most abundant carbohydrate found in nature?
cellulose
name the sugars found in the various foods…
…fruit? - fructose
…honey? - fructose & glucose
…table sugar? - sucrose
…corn syrup? - glucose
lipid
a substance from animal or plant cells that is soluble in solvents of low polarity and insoluble in water
fat
an ester formed by the reaction of glycerol with 3 fatty-acid units; a triglyceride or triacylglycerol
fatty-acid
a carboxylic acid that contains 4 to 20 or more carbon atoms in a chain
triglyceride
an ester of glycerol with 3 fatty-acid units; also called a triacylglycerol
oil (food)
a substance, formed from glycerol & fatty-acids, which is liquid at room temperature; “liquid fats”
saturated fat
a triglyceride composed of a large proportion of saturated fatty acids esterified with glycerol
iodine number
the mass in grams of iodine that reacts with 100 grams of a fat or oil; an indication of the degree of unsaturation
- high iodine number = high degree of unsaturation
- low iodine number = high degree of saturation
polyunsaturated fat
a fat containing fatty-acid units that have two or more carbon-carbon double bonds
