chapter 7 proteins Flashcards
proteins are complex organic molecules made up of
amino acid
protein composed of which elements
carbon, hydrogen, oxygen
only macronutrient that contains nitrogen
protein
the body uses proteins to make or function as
new cells, components of cells
hair, nails
enzymes
lubricants
clotting compounds
antibodies
compounds that maintain fluid and pH balance
certain hormones and neurotransmitters
energy source
edema
swollen tissue
edema arterial end
fluid forced into tissue spaces by blood pressure generated by pumping action of the heart
edema venous end
fluid drawn into bloodstream by the proteins as blood pressure declines in the capillaries
human proteins have ___ amino acids
20
each amino acid is composed of
1. ____ group
2. ____ group
3. ____ group
amino or nitrogen containing group
R group
acid group
R group
varies, used to identify molecule
essential amino acids
cannot be made by the body or in amounts great enough to meet needs, must be supplied by the diet
how many amino acids are essential
9
nonessential amino acids
can be made by the body
how many amino acids are nonessential
11
some of the nonessential amino acids are “conditionally essential” which means they
become essential in certain situations
9 essential amino acid names
histidine
isoleucine
leucine
lysine
methionine
phenylalanine
threonine
tryptophan
valine
11 nonessential amino acid names
alanine
aspartic acid
asparagine
glutamic acid
serine
agrinine
cysteine
glutamine
glycine
proline
tyrosine
conditionally essential amino acid names
arginine
cysteine
glutamine
glycine
proline
tyrosine
food from ____ sources typically have more protein per serving than similar quantities of foods from ___
animal
plants
___, ____ and ____ supply more protein per serving than fruit or edible leaves, roots, flowers, and stems of vegetables
seeds
tree nuts
legumes
legumes
plants that produce pods with a single row of seeds, such as soybeans, peas, peanuts, lentils, beans
which food has the most amount of protein per serving
chicken breast
high quality protein
contains all 9 essential amino acids in amounts that support protein deposition in tissue and a Childs growth
high quality protein is most ___ products
animal
plant sources that are high quality protein
soy, qunioa
low quality protein
lacks or has inadequate amounts of one or more essential amino acid
limiting amino acids
essential amino acids in lowest amounts in a food
most ___ sources are low quality protein
plant
cells assemble the 20 amino acids in specific sequences and lengths according to
information provided in DNA
amino acids are connected by
peptide bonds
polypeptide forms when
two or more amino acids form a chain
peptides
small chains of amino acids
protein synthesis begins with
DNA in the cells nucleus
gene
portion of DNA that contains information about the order of amino acids in a specific protein
___ and ___ help to form the protein
mRNA, tRNA
mRNA is formed by
transcription and “read” by ribosomes during translation
tRNA brings
amino acids to the ribosomes during translation
when translation is complete, the polypeptide
chain coils and folds into a 3D shape for that specific protein
basic steps of protein synthesis:
1. in the cell nucleus, protein synthesis begins when
a section of DNA unwinds, exposing a single portion
basic steps of protein synthesis:
2. the gene undergoes _____, forming ___
transcription
mRNA
basic steps of protein synthesis:
3. mRNA transfers information concerning the amino acid sequence from the ____ to ____
nucleus to ribosome protein manufacturing sites in the cytoplasm
basic steps of protein synthesis:
4. during the translation process, ____ read mRNA. the coded instructions indicate
ribosomes
which amino acid to add to the polypeptide chain and its sequence
basic steps of protein synthesis:
5. each specific tRNA molecule conveys
a particular amino acid to the ribosome
basic steps of protein synthesis:
6. at the ribosome, the amino acid that has been delivered
attaches to the peptide chain
basic steps of protein synthesis:
7. when the translation process is complete, the ribosome _______ and the new protein undergoes ______
releases the polypeptide
further processing
the shape of a protein is important because it
determines the activity of the protein
if the wrong amino acid is inserted in the chain
a genetic defect can occur
sickle cell anemia
defective hemoglobin cannot transport oxygen efficiently
denaturation
altering a proteins natural shape and function by exposing it to various conditions
denaturaition can can be caused by
heat, acid, physical agitation
chemical digestion of protein begins in the
stomach
_______ denatures protein
hydrochloric acid
the enzyme ____ digests proteins into smaller polypeptides
pepsin
polypeptides are broken down further in the
small intestine
the enzymes ___ and ____ break down polypeptides into shorter peptides and amino acids
trypsin
chymotrypsin
enzymes from absorptive cells of the small intestine break down shortened peptides into
dipeptides, tripetides, amino acids
protein absorption occurs in the
small intestine
amino acids travel to the ___ via the___
liver
hepatic portal vein