unit 1 Flashcards
Describe the difference between matter and element
matter= anything that takes up space and has mass
element=building blocks of matter
Whats the difference between a molecule and compound
molecule= atoms of same element
compound= atoms of different elements
What are the most abundant elements in our bodies
Nitrogen, carbon, oxygen, calcium and hydrogen
How do isotopes differ from eachother
they have different number of neutrons
What is the relationship between electrons and chemical bonds
chemical bonds happen because of valence e- who want to achieve an octet
Which bonds are formed between molecules
H-bonds, covalent and ionic
which bonds are formed between atoms
ionic/(polar and non-polar)covalent bonds
what are the 2 types of strong bonds and how do they differ
covalent (sharing e-) and ionic (complete transfer of e-)
What is the relationship between covalent bonds, electronegativity, polar and nonpolar
compounds?
polarity depends on difference in electronegativity between atoms
Polar bonds happen when atoms do not share electrons equally
Non-polar bonds share e- equally
Of the most abundant elements in your body, what is the relative electronegative to each other?
Ca
What are examples of non-polar molecules and polar molecules?
non-polar= CH4
polar= H2O
what are the 3 types of weak bonds
1-H-bonds
2-Van der Waals interactions
3-Ionic bonds in water
whats the purpose of weak bonds
they allow molecules to interact, provide stability in large molecules,
adhering molecules briefly when they collide
why do ionic bonds weaken in water
each ion is partially shielded because it interacts with water (they dissociate easily in water)
in photosynthesis where does oxygen come from
water and CO2
Why do all organism need water
the main source of oxygen (medium of life)
why is water polar
the slight positive charges on the hydrogens and the negative charges of oxygen create partial charge/dipole moment making the molecule polar
Define cohesion
the ability of molecules of same substance to stick together
define adhesion
the ability of molecules to stick to another material
define tension
mesures how difficutl it is to break/stretch surface of a liquid
what are the four main properties of water
1-solvent
2-C.A.T
3-temperature buffer
4-Density
Why is water a universal solvent
can dissolve any polar substance
what is hydration
solvation for which the solvent is water
True of false
water can dissolve non polar substances
false
how does water dissolve ionic substances
in ionic solid, the partial + charge of hydrogens attract the anion an - charge of oxygen attract cation= they separate and solid is dissolved
How can water dissolve non polar substances like sugar
Water forms H-bonds with outer molecules and removes the monosaccharides individually until they are dispersed throughout the solution
What other kind of macromolecules can dissolve in water
proteins if they have ionic areas
where can water be found as a solvent in organisms
in the blood, inside cell (cytosol), plant sap
What cause cohesion between water molecules
H-bonding
Why is cohesion and adhesion useful for organisms
allows for capillary action
Define capillary action
tendency of water to move in narrow tubes, against gravity (ex: water moves from root to leaves)
why does water have a strong surfcae tension
strong attraction between molecules (H-bonds)
wnat is the max amount of H-bonds that a molecule can form
4
How does each state of water vary in terms of H-bonds
in solid water each molecules have 4 H-bonds, liquid have less and air have practically none.
Why is it important for water to have a high specific heat
allows water to absorb large amount of heat before its temperature increases
How does water act like a temperature buffer
high specific heat= better ability to resist temperature change
Why is moderation of temperature important to maintain life
allows oceans, lakes, etc to maintain relatively constant temperature= stable environment
What is evaporative cooling
when water is heated , the molecules that are released fatser enter gas phase and the water left behind is more cool
how do organisms utilize evaporative cooling
to help cool themselves (perspire/transpires)
What are the properties of ice
contains more stable hydrogen bonds
Ice is less dense than liquid water
Why is it important that ice is less dense than water
if ice sank it woud freeze the bottom of the oceans=life unsustainable
what is ionization
water molecules can break apart in aqueous solutions (H+ and OH-
What is the effect of a acid on pH of solution
decreases pH (donates H+)
What is the effect of a base on pH of solution
increases pH (donate OH-
Describe a pH buffer
substance that resists changes in pH by either accepting H+ ions in excess and donate H+ when they’re missing
Name a buffer
blood
Why is it important for pH in cells and in other body fluids to be tightly regulated?
any pH change could disrupt ionic/h-bonds between amino acids structure = unstable protein
can alter protein shape= cant function
How does carbonic acid (H2CO3) play a role in the fluids of the body?
acts as buffer in human blood to keep it within range
what can cause blood pH to go below range
respiratory disease= the body can get rid of CO2 fast again= increase H+ concentration= acidosis
what can cause blood pH to go above range
hyperventilation= too much CO2 expelled= decrease in H+= alkalosis
Why do shells in aquatic animals thin and become fragile as oceans become more and more acidic?
they require calcium carbonate to make their shells and increase in H+ disturbed and it causes this rxn :H+ + CO32- =HCO3- which decreases calcium carbonate production
Where do autotrophs obtain organic carbon? Heterotrophs?
autotrophs obtain their carbon from light or chemical energy (atospheric CO2)
heterotrophs obtain their carbon from organic compounds
what is an biomolecule
proteins, DNA, carbohydrates and lipids
whats an organic molecule in biology
compounds formed by the living that contain a carbon hydrogen backbone
Whats a carbon skeleton
carbons of organic compounds
whats a functional group
elements that are attached to the carbon skeleton (noncarbon grps)
Which properties of carbon make it a good building block for organic biomolecules?
Has a tetravalence which makes large/complex molecules possible.
Which other elements make up the major atoms used to build biomolecules?
hydrogen, nitrogen, oxygen
When carbon is bound to four other atoms, what shape does the molecule generally take?
tetrahedral shape
what is polarity
the measure of electronegativity between two atoms (how much they can pull e- )
List the seven functional groups discussed
hydroxyl grp
carbonyl grp
carboxyl grp
amino grp
sulfhydryl grp
phosphate grp
methyl grp
what are the general properties of the hydroxyl grp
OH-
polar grp, doesnt dissociate in water
what are the general properties of the carbonyl grp
CO-
provide some degree of polarity.
what are the two types of carbonyl groups
aldehydes and ketones
whats the difference between aldehyde and a ketone
aldehydes contain the carbonyl carbon bonded to AT LEAST one H
ketones have carbonyl carbon bonded to 2 other carbons
True or false
simple sugars can only be aldehydes
false can also be ketones
What structures do monosaccharides take on when mixed with a fluid (i.e. water)
ring structure
what are the general properties of the carboxyl grp
-COOH
weakly acidic (can release proton)
provides polarity
Carboxyl group is an important part of what macromolecule (monomer)
amino acids (in protein)
what are the general properties of the amino grp
-NH2
polar, allows amino acids to act as organic buffers (can be acid or base ), weakly basic
In amino acids does the amino group accept or donate a proton
accepts a proton
why can amino acids act as natural buffers
they have a carboxyl grp (acid) and an amino grp (basic) in their structure.
what are the general properties of the sulfhydryl grp
-SH
non polar, forms disulfide bridges
what are the general properties of the phosphate grp
-OPO3 2-
polar, can donate H+ into solution= weakly acidic
Why are disulfide bridges important
strong bonds that help stabilize the internal structure of proteins (form cross links)
In what important molecules can phosphate groups be found
in phospholipids, nucleotides and ATP
Why is atp so high in energy
the 3 phosphate grp bonded to eachother are highly unstable (repulse one another)= high E bonds
what are the general properties of the methyl grp
-CH3
nonpolar, acts as an identity tag to molecules (read by enzymes)
Where can sulfhydryl groups be found
in proteins (internal structure)
Where can amino groups be found
amino acids, nitrogenous bases of DNA/RNA
how does the carbonskeleton contribute to the diversity of organic biomolecules
the arragement of the carbon skeleton gives them different properties
how do the functional groups contribute to the diversity of organic biomolecules
they can give them unique properties/behaviors
define isomers
compounds with the same molecular formula but different chemical structures=diff properties
what are the 3 kinds of isomers
structural-geometric-optical
Whats the difference between a structural and geometrical isomer
structural: different covalent arrangement of their atoms
geometric: same covalent arrangement but different spatial arrangement
what are the 2 types of geometric isomers
cis and trans isomers
How do cis isomers differ from trans isomers
cis= groups on same side
trans= grps on opposite sides of the bond
give an example of a geometric isomer
rhodopsin
what are enantiomers
isomers that are the images of each other (cant be superimposed)
True or false
Cell will only recognize one enantiomer
true
Why is it important to be aware of enantiomers
give different effect to drugs (ex: thalidomide)
Define a monomer and a polymer
monomer: small organic molecule that are joined to make larger molecule=macromolecules
polymers: thousands of monomers covalently joined together.
Describe a hydrolysis reaction
breaks down polymers into monomers by adding water to break the bonds
Describe a condensation/ dehydration reaction
removing H/OH- grps to link monomers and form polymers
requires energy and a catalyst
Why do hydrolysis and condensation reactions require enzymes
to speed up the reactions
What are the major functions of carbohydrates in cells. (Give some specific examples for each)
short term energy storage (sugar) and intermediate energy storage (glycogen and starch)
structural components in cells (chitin and cellulose)
What is the general ratio of the three main atoms in a carbohydrate?
1:2:1
Fill in the blank :
Carbohydrate are ____ and ____ compounds with multiple -OH grps
aldehyde and ketone
what are the common disaccharides found in our bodies
sucrose, maltose and lactose
What are three monosaccharides that mammals can metabolize? How do they differ from each
other?
glucose, fructose and galactose
they all have different structures but the same chemical formula (structural isomers)
whats the most common monosaccharide
glucose
List the structural characteristics of a monosaccharide that can vary
spatial arrangement of the carbon skeleton, the position of carbonyl grp, size of skeleton
Define aldose
the carbonyl group is at the end
define ketose
the carbonyl grp is in the middle
Whats a triose sugar
has 3 carbon, smallest sugar
whats the difference between a pentose and hexose sugar
pentose=5 carbon
hexose= 6 carbon
where can pentose sugars be found
in DNA
Why do monosaccharides have isomers
They occur naturally in the wild and they also provide polysaccharides with different properties
What is glycosidic linkage
covalent bond that links monosaccharide together after dehydration synthesis run
what are the two kinds of glycosidic linkage
alpha and beta
what are the 2 isomeric forms in which glucose exists
β-glucose and α-glucose
glucose is the end product of what reaction
photosynthesis
glucose is a reactant in which rxn
cellular respiration
How does your body maintain homeostasis of glucose in your blood?
The pancreas secretes hormones (insulin and glucagon) that regulates the bloog sugar levels
Which organs and tissues are involved in maintaining blood glucose level constant
liver and pancreas
What is the function of insulin
it decreases blood glucose level by :
1. stimulating uptake of glucose in muscle
2. preventing breakdown of glycogen → glucose in the liver
3. stimulates adipose cell to store glucose as fat
How does insulin function
the hormone binds to receptors on surface of fat, mucle and liver cells and promotes the uptake of glucose inside the cell
What is the function of glucagon
it increase the glucose level in the blood by:
1.Stimulating conversion of glycogen→ glucose
2. breaks down proteins into amino acids (muscle cells)
3. breaks down fats in adipose cell to release fatty acids
how does breakdown proteins release blood glucose
amino acids are involved in gluconeogenesis (synthesis of glucose )
What kind of disorder is diabetes mellitus
endocrine disorder (hormonal isssue)
What cause diabetes
deficiency of insulin (type 1)
decreased reponse to insulin (type 2)
What are the symptoms of diabetes
excess pee, low energy, dehydration, hunger, etc…
Why are disaccharides and starch important in our bodies
they are the main source of glucose in food
Which monosaccharides are involved in the following disaccharides: maltose,
sucrose, lactose.
Maltose: glucose +glucose
Sucrose: fructose +glucose
Lactose : galactose+ glucose
what is lactose intolerance
drop in lactase production
What is lactase and why is it important
enzyme that breaks down lactose in our small intestine
In what organ are carbohydrates usually absorbed as monosaccharides
the small intestine
What does lactorance intolerance cause
the lack of lactase in small intestine cause lactose to pass in the large intestine and gets broken down by bacteria= causes gases and acids
What is the treatment for lactose intolerance
removing lactose from the diet
What are oligosaccharides
small sugars (2-6 units) that are attached to glycoproteins and some glycolipids
What is the function of oligosaccharides
serves as tags to identify cells (heart, muscle cell, etc)
What is the cause of flatulence from eating legumes?
particular oligosaccharides present in beans/legumes that our body can digest (no enzymes for it)
What is the role of glycoproteins
serve in cell adherence, protection and identification
Where are glycoproteins found generally
in the ECM
also found in mucus
why do polysaccharides vary in their properties
composed of different isomers and have different structures (branched, webbed, etc)
Describe the two functional classes of polysaccharides.
Energy storage : molecules that can easily be broken down
Structural: molecules with specific 3-D arrangements
What are the characteristics of α-linkages
present in sugars/starch that allows molecules to be broken down and used as energy source
What are the characteristics of β-linkages
occurs in structural molecules and cant be digested by most eukaryotes
Why is glycogen is an efficient storage molecule
can be broken down into glucose-6-phosphate which give short term energy for metabolism
What is starch hydrolized into and what enzyme is responsible for that
amylase hydrolizes starch into maltose
where can amylase be found
saliva and secreted by pancreas
What makes the structure of cellulose great for fibers
extensive unbranched chain of β-glucose which allows for H-bonds inbetween cellulose molecules
What is dietary fiber?
carbs needed for proeper digestion (ex: cellulose) but we lack the enzyes to hydrolize them into monosaccharides (NOT USED FOR ENERGY)
Describe the importance of dietary fiber in our diet
fiber adds bulk and absorbs water= makes feces larger and softer:
-reduces pressure for defecation
-can lower cholesterol
-slows rate of carb absorption
Describe the structure of chitin
unbranched polysaccharide
Whats the only polysaccharide with an amino acid attached to it
chitin
What is the function of chitin
protective exoskeleton of arthropods
ccan also be used for surgical threads
Where is peptidoglycan found
in cell walls of bacteria
What is the difference between gram positive and gram negative bacteria
gram (+): cell wall with a lot of peptidoglycan
gram (-): cell wall lacking peptidoglycan
why is gram staining a valuable too in medicine
allows us to identify why antibiotic will be efficient to treat an infection
ex: penicillin kills gram positive bacteria
what is the difference in bonding between structural and energy storage polysaccharides
structural: β-linkages
energy: α-linkages
Why are lipids grouped together
they’re all hydrophobic molecules
What are the classes of lipids
neutral fats (fatty acids and triglycerides), phospholipids and steroids,
true or false
Triglycerides are neutral fats
true
What is the function of neutral fats in organism
serve in energy storage, insulation of organs
What is the structure of triglycerides
1 glycerol and 3 fatty acids (long hydrocarbon tail with carboxyl grp)
How many reactions does it take to make one triglyceride
3 dehydration reactions
What bonds join glycerol with 3 fatty acids
ester linkages
What allows tryglycerides to have different properties
the fatty acids chain
what are the 3 kinds fatty acids
1-saturated fatty acids: no double bonds in the hydrocarbon tail
2- monunsaturated: 1 double bond
3-polyunsaturated: 2 or more double bonds
Fill in the blank:
saturated fatty acids have a ____ structure while mono/polyunsaturated fatty acids have a ______ structure
linear and bent
how do the structure of fatty acids affect their state at room temperature?
bent= molecules cant stack well=liquid at room temperature
linear=molecules can stack= solid at room temp
What kind of fatty acid can come in the cis or trans shape
unsaturated
what is the general structure of a cis unsaturated fatty acid (orientation of the bond)
both H are on the same side of the double bond (creates the bend)
what is the general structure of a trans unsaturated fatty acid (orientation of the bond)
Hydrogens are on opposite side of double bond (creates amore rigid/linear structure)
Which kind of unsaturated are found naturally and which are processed food (cis or trans)
natural:cis
processed: trans
why are trans fat bad for our health
overconsumption of trans fat can lead to blockages in our arteries (since they’re dense and solid)
how are trans fats synthesized
through hydrogenation
Describe hydrogenation
H atoms are added to cis unsaturated fatty acids= makes fat more solid at room temp this converts cis bonds→ trans bonds or make fat unsaturated
Describe briefly how triglycerides are digested
fats are emulsified by bile salts (made by the liver). They are then hydrolized into fatty acids and absorbed by cells in lining of small intestine
What happens to fatty acids onced they’re absorbed by the small intestine
they are reassembled into chylomicrons
What’s the function of chylomicrons
lipoproteins that carry lipids in the blood/to other cells in the body
describe the general structure of lipoproteins
spherical molecules with hydrophobic interior and hydrophilic exterior
embedded with proteins
What are LDLs
low-density liproteins that carry fats produced by the liver to other cells
what are HDLs
high-density lipoproteins that return to the liver after delivering fatt cells to the body
what differentiates HDL from LDL from chylomicrons
HDL are mostly proteins
LDL are mostly fat
Both LDL and HDL are involded with the liver while chylomicrons are made in small intestine
LDL/HDL are the remaining chylomicrons with the excess fats
What is the structure of steroids
4 fused carbon rings with various functional grps attached
Give examples of steroids
cholesterol, testosterone, vitamins, bile salts, etc
what are annabolic steroids
synthesized steroids similar to testosterone that promotes muscle growth
How is cholesterol carried through the blood
through LDLs/HDLs
How can we determine if someone has good or bad cholesterol
by mesuring HDL, LDL levels in the blood
what does it mean when someone has “bad” cholesterol
high levels of LDLs in the blood because of high trans fat diet= can cause plaque in blood vessels
what does it mean when someone has “good” cholesterol
high levels of HDLs circulating in the blood to reduce presence of cholesterol in the blood
Describe the structure of phospholipids
glycerol, 2 fatty acids, phosphate grp (- charge) and an alcohol (choline)
What special traits do phospholipids have
theyre amphipatic
What is the main function of phospholipids
make up all cell membrane
what are the 2 types of phospholipids that can be found in cell membrane
phosphoglyceride and shingolipids
what makes shingolipids different
they have a single leg and have amino alcohol instead of glycerol
in what cells are shingolipids more abundant
neurons, spin cells, lungs
What happens to sphingolipids in patients with Tay-Sachs disease?
accumulation of shingolipids in nerve cells which leads to the destruction of nervous system
which group is responsible for the specific properties of an amino acid
The side chain (R)
What do we call the bond that links amino acids to make a polypeptide
peptide bonds
What are α, β and γ forms of amino acids?
α: α carbon is bonded to the carboxyl and amino grp
β: β carbon is linked to amino acid and α carbon is linked to carboxyl grp
γ: GABA amino acid (3 carbons)
true of false
the gamma form of amino acids is the most common
false
alpha form is the most common
Fill in the blank
L and D isomers of amino acids are ______.
enantiomers
Which isomers of amino acids are used as building blocks for proteins
L isomers
Why are amino acids great biological buffers
depending on the environment they either accept a proton to increase pH (becomes protonated) or donates a proton to lower pH (becomes dissociated)
Whats a zwitterion
the amino acid present at a dipolar ionic state when pH=7.4 (neutral)
What are the 3 classes side chain attached to amino acids
polar, electrically charged non polar (neutral)
List 4 hydrophobic amino acids
leucine, methionine, isoleucine, tryptophan
Whats an essential amino acid
amino acid that an animal can’t synthesize on their own, so it must come from food
Define a polypeptide
repeating structure of amino acids linked together
what provides polarity to the polypeptide
the N-terminus and C-terminus
whats the difference between a polypeptide and a protein
protein: macromolecule made of one or more polypetide coiled/twisted together
polypeptide: unique amino acid chain
Describe the primary structure of a protein
unique sequence of amino acids
Describe the secondary structure of a protein
H-bonds between the amino grps and carboxyl grp (alpha helix or beta pleated sheets)
Describe the tertiary structure of a protein
3-D shape of the folded protein cause by interaction amongst the R grp (H-bonds, disulfide bridges, ionic bonds, hydrophobic interactions )
what are the common types of tertiary structure
globular (mix of beta pleated sheets and alpha helix) or fibrous (mostly alpha helix)
Describe the quaternary structure of a protein
interactions amongst polypetide chains
True of false
The protein shape and primary structure defines its function
true
what is the function of chaperonins
complex molecules that ensure a proetin is properly folded and assumes the right conformation
Whats a monomeric protein
no quaternary structure
whats an oligomeric protein
two or more polypeptide chains
Define denaturation
disruption of the secondary and tertiary structure of a protein which destroys its shape=can no longer function
Would a change in the amino acid chain be considered as denaturation
no , denaturation stems from external factors. an error in amino acid chain can only be cause by a genetic mutation
what factors can cause denaturation
heat, alcohol, pH imbalance
What is a prion
a misfolded protein that becomes an infection agent and force other proteins to misfold.
How does prion disease occur
the disfunctional version of the protein binds to a normal one and causes it to misfold, this new prion then goes on to denature other proteins.
what are the 8 functions of proteins
1- enzymatic
2-defensive
3-Structural
4-Contractile and motor
5-Transport
6-Receptor
7-Storage
8-Chemical messanger
Whats the function of enzymatic protein
accelerate chemical rxn
ex: any enzyme
whats the function of storage proteins
serve as source of amino acids for embryos/infant
ex: casein or ovalbumin
whats the function of chemical messenger proteins
coordinate an organism’s activity=hormones or neurotransmitters
ex: insuline or ACh
whats the function of contractile proteins
functions in mouvement
ex: actin and myosin
whats the function of defensive proteins
protection against diseases
ex: antibody proteins=antigens that help destroy the foreign body
whats the function of transport proteins
transport substances in the body/cells
ex: hemoglobin
whats the function of receptor proteins
regulate response of the cell to stimuli
ex: receptors in nerve cells
whats the function of structural proteins
provide support (in cell membrane, muscle tissue, tendons, ligaments)
ex: collagen, elastin
Whats a simple protein
only made of amino acids
whats a conjugated protein
contains amino acids and another chemical grp and a prosthetic grp
