Biology Flashcards
Any substance that takes up space and has mass
Matter
Substance that has specific chemical and physical properties
Element
The smallest unit of matter that still retains all the chemical properties of an element
Atom
Whenever two or more atoms join together
Molecules
Contain carbon atoms arranged as ling chains or rings, and these carbon atoms tend to bond with hydrogen, oxygen, or nitrogen atoms
Organic molecules
Strong attractive forces that hold atoms within a molecule
Intramolecular forces
________ exist between molecules, and they are far weaker than ______
Intermolecular forces; intramolecular forces
_________ forces are significant because they determine physical properties
Intermolecular forces
Molecules that have the potential of binding to other identical molecules through chemical reactions
Monomers
Formation of polymers
Polymerization
Substances that have a large number of units (monomers) bonded together
Polymers
Macromolecules that contain carbon, hydrogen, and oxygen atoms
Carbohydrates
_______ contain roughly one carbon atom per water molecule
Carbohydrates
“One sugar”
Monosaccharides
________ have a ratio of precisely one carbon per water mater molecule
Monosaccharides
Monosaccharides will usually have anywhere from ____ to ____ carbon atoms
3 to 7
Five carbon sugars
Pentoses
Six carbon sugars
Hexoses
Whenever a linear pentose or hexose sugar converts to a ring structure, it forms a _______
Hydroxyl (-OH) functional group
A hydroxyl group that points down creates a ______ sugar
Alpha
A hydroxyl group that points up creates a ______ sugar
Beta
“Two sugars”
Disaccharides
Disaccharides form when two monosaccharide monomers join together via
Dehydration reaction (also known as condensation reaction)
Water adds to a covalent bind and splits monomers apart
Hydrolysis reaction
The bond formed between a carbohydrate and another molecule
Glycosidic bond
Contains one glucose and one fructose
Sucrose
Contains one galactose bound to one glucose
Lactose
Contains two glucose monosaccharides linked together
Maltose
Long polymers of monosaccharides
Polysaccharides
A crucial storage polysaccharide in plants, containing many glucose monomers in linear forms as well as branched forms
Starch
Linear plant starch that contains a-1,4-glycosidic bonds
Amylose
Branched form of plant starch that contains a-1,4-glycosidic bonds and a-1,6-glycosidic bonds
Amylopectin
A critical storage polysaccharide found in humans that contains many glucose monomers. It is more branched than amylopectin
Glycogen
Contains a-1,4-glycosidic bonds and a lot of a-1,6-glycosidic bonds. It is primarily stored in liver and muscle cells.
Glycogen
It is broken down to release glucose monosaccharides to cells that need energy
Glycogen
Structural polysaccharide found in plant cell walls, wood, and paper
Cellulose
A glucose polymer that contains b-1,4-glycosidic bonds
Cellulose
Cellulose forms linear strands that pack together in parallel, where adjacent strands are held together by
Hydrogen bonds
Humans cannot digest cellulose; instead, it passes through our digestive tracts as
Fiber
Virtually identical to cellulose, and it is found in the cell walls of fungi and in the robust exoskeleton of insects
Chitin
Chitin is a polymer of _______. One of the hydroxyl groups in each glucose molecule gets replaced by a functional group containing nitrogen
N-acetylglucosamine
All of the proteins that are exposed by the cell form a
Proteome
All proteins contain polymers called _______. Each polypeptide contains monomeric subunits called ________.
Polypeptides; Amino acids
Alpha carbon center which is attached to an amino group, hydrogen atom, and carbonyl group
Amino acid
At physiological PH in the human body, the amino group tends to be _______ and the carbonyl group tends to be ________
Protonated; Deprotonated
Variable group in amino acids
R group
Every amino acid monomer is attached to its neighbor via
Peptide bonds
Amino acids form peptide bonds with each other via
Dehydration/condensation reactions
A peptide bond is called _______ when it involves amino acids
An amide bond
Amine bonded to a carboxylic acid
Amide bond
Polypeptides are said to have both
N-terminus (amino) and C-terminus (carbonyl)
Specific order or sequence of a peptide, which is determined by DNA genes. All proteins have this.
Primary structure
Folds that occur in a polypeptide chain due to intermolecular interactions between atoms of the polypeptide backbone
Secondary structure
The amino acid structural features other than the R-group. The secondary structure does not involve R-group atoms
Polypeptide backbone
Most common type of intermolecular force that leads to secondary protein structure
Hydrogen bonding
Hydrogen bonds can only occur between
Hydrogen, fluorine, oxygen, or nitrogen
Two of the most common secondary protein structures
Beta-pleated sheets and alpha helices
Three dimensional structure of larger polypeptide chains, which occurs as a result of interactions between R-groups of the various amino acids
Tertiary structure
Ionic bonding, hydrogen bonding, dipole-dipole interactions, and London dispersion (van der Waal) forces
R-group interactions
Another critical R-group interaction that can cause tertiary structure
Hydrophobic interactions
Contain sulfur in its R-group and can create disulfide bonds with each other
Cysteine
Tertiary structure interactions are usually not covalent; disulfide binds are an _______ to this
Exception
Refers to large proteins that have multiple subunits which come together by the same general interactions used in creating tertiary structure
Quaternary structure
While there are multiple polypeptide chains in a quaternary structure, we consider the entire structure to be
One protein
_________ and ________ components are fundamental to a protein because they relate to the function of that protein
Structural; compositional
Common tetramer protein with primary, secondary, tertiary, and quaternary structure
Hemoglobin
whenever a functional protein loses its higher order
structures
Protein denaturation
Protein denaturation can occur by
excess temperature, chemicals, pH changes,
and radiation, to name a few
all of the information necessary for the
folding of those proteins (some denatured proteins) is contained directly within
The amino acid sequence
Molecules that increase reaction rates
Catalysts
Catalysts do not affect the __________ of a reaction
Spontaneity
________ are not used up by the reactions they manipulate,
meaning the reaction does not change them in any way.
Catalysts
Catalysts ________ activation energies to speed reactions.
Lower
the amount of energy a chemical reaction requires to progress
Activation energy
catalysts do not affect the energy of
Reactants or products
biological, globular (usually) protein catalysts that speed up specific forward and reverse reactions by lowering their activation energies.
Enzymes
_________ only change the energy of the transition state, not of the reactants or products.
Enzymes
Enzymes catalyze reactions by binding to reactant molecules, which are called
Substrates
An enzyme’s __________ is where substrates bind.
Active site
An enzyme’s ___________ measures how efficient an enzyme is in converting substrate to product
Specificity constant
Non-protein molecules that assist enzymes in the reactions they manipulate.
Cofactors
a ribonucleic acid (RNA) molecule that is capable of acting as an enzyme by changing the speed of reactions as they progress from reactants to products.
Ribozyme
Coenzymes are organic cofactors, and these usually include things like
Vitamins
Enzymes that are bound to their cofactor
Holoenzymes
An enzyme that is lacking (not bound to) its cofactor.
Apoenzyme
Cofactors that tightly/covalently bind to their enzyme in a holoenzyme are known as
Prosthetic groups
A form of enzyme regulation, where inhibitors compete with substrates for active sites.
Competitive inhibition
Adding more substrate will only increase the speed of catalysis until all active sites are occupied
Enzyme saturation
when an inhibitor binds to the allosteric site of an enzyme – a different location that is not the active site of enzyme catalysis.
Noncompetitive inhibition
We cannot outcompete allosteric inhibitors by adding more substrate, which is why they are known as ____________________. The rate of enzyme catalysis is unaffected by
increasing the substrate concentration.
Noncompetitive inhibitors
_________ store energy, provide insulation, contribute to cell membranes, and lead to the synthesis of critical hormones.
Lipids
a small, organic alcohol molecule that has three carbons and three hydroxyl groups
Glycerol
a long hydrocarbon tail attached to a carboxylic acid.
Fatty acid
Fats are produced by
Dehydration/condensation reactions
The hydroxyl groups of the glycerol molecule react with the carboxylic acids of fatty acids to produce
An ester linkage
The addition of water to a fat’s ester bonds will break the fatty acids off the glycerol backbone by
A hydrolysis reaction
If a fatty acid tail has no double bonds, it is
Saturated
At room temperature, saturated fats are
Solid
__________ fatty acids can possess one or more double bonds because they do
not have full hydrogen saturation
Unsaturated
Fatty acids with one double bond
Monounsaturated
Fatty acids with two or more double bonds
Polyunsaturated
create kinks in the fatty acid chain because the hydrogens associated with the double bond remain on the same side.
Cis-unsaturated fatty acids
cis-unsaturated fats tend to be ________ at room temperature
Liquid
________ have hydrogens that go to opposite sides of the double bond, which makes them pack together tightly
Trans-unsaturated fatty acids
In nature, transunsaturated fats are
Rare
__________ is performed to give cheaper oils (like canola oil) the desirable room-stable properties of more expensive products, like butter.
Industrial hydrogenation
___________ are a unique type of lipid (fat) found in cell membranes
Phospholipids
Each phospholipid has a three-carbon glycerol backbone attached to ___________ and ___________.
One phosphate group; Two fatty acid tails
Looks virtually the same as a phospholipid; however, these contain a carbohydrate molecule in place of the phosphate group.
Glycolipid
A class of lipid that makes up around 30-50% of a eukaryotic cell membrane.
Cholesterol
contains four hydrocarbon rings and is also amphipathic, which allows it to interact with various regions of the phospholipid bilayer.
Cholesterol
Several factors influence the fluidity of a membrane, including ___________, ____________, and _____________ in the phospholipid fatty acid tails.
temperature, cholesterol, and the degree of unsaturation
The ability of cholesterol to interact with the cell membrane is beneficial to the overall _______ of the membrane.
Fluidity
maintains some distance between the phospholipids when it is cold, but it also holds the phospholipids together when it starts to get hot.
Cholesterol
When it is cold, cells _________ fatty acid unsaturation in their membranes to ________ rigidity and maintain fluidity
Increase; decrease
This organ makes cholesterol
Liver
A starting material for vitamin D and a precursor to bile acids
Cholesterol
The most common steroid precursor (meaning it can be made into steroids)
Cholesterol
Fused structures composed of three six-membered rings (cyclohexanes) and a five membered ring (cyclopentane)
Steroids
Contain a coat of phospholipids, cholesterol, and proteins. They also have a lipid core that contains more cholesterol and triglycerides.
Lipoproteins
Low density of proteins. They are generally considered to be unhealthy because they deliver cholesterol to peripheral tissues via the bloodstream
Low-density lipoproteins (LDLs)
High density of proteins. They are generally considered to be healthy because they take cholesterol away from peripheral tissues and deliver it to the liver. Once at the liver, the cholesterol can be used to make bile acids, which aid in fat absorption as was mentioned above. They are the “good” cholesterol.
High-density lipoproteins (HDLs)
Contain long fatty acids that are connected to monohydroxy alcohols by ester linkages.
Waxes
Long fatty acid carbon chains that have conjugated double bonds and six-membered rings at each end. They function as pigments that provide color to plants and animals.
Carotenoids
Pentose (five-carbon) sugar attached to a nitrogenous base.
Nucleosides
__________ is a pentose sugar attached to a nitrogenous base and a single phosphate group. Nucleic acids are polymers made of this.
Nucleotides
A and G nitrogenous bases are known as
Purines
C, U, and T are known as
Pyrimidines
Purine molecules have ____ rings, while pyrimidines have just ____ ring
Two; One
RNA nucleotides have _______ sugars with a hydroxyl group on the 2’ (“two prime”) carbon.
Ribose
DNA nucleotides are slightly different because they have __________ sugars, meaning the 2’ carbon does not contain oxygen.
Deoxyribose
RNA is _________ (less stable) than DNA because of its 2’ hydroxyl group.
More reactive
Phosphate groups attach to the nucleotide sugar at the
5’ carbon
The 5’ phosphates of one nucleotide connect to the __________ of another nucleotide in nucleic acid polymers.
3’ hydroxyl
Create the sugar-phosphate backbone of nucleic acid polymers.
Phosphodiester bonds
5’ end has a free __________ group, while the 3’ end has a free _________ group.
Phosphate; Hydroxyl
Add to growing nucleic acid polymers by losing two phosphates (as pyrophosphate) to form a phosphodiester bond with the free hydroxyl at the 3’ end of the polymer - this is how nucleic acid polymerization occurs.
Nucleoside triphosphates
Adenine and thymine (or uracil) make ______ H-bonds, while cytosine and guanine make ______ H-bonds.
Two; Three
The cell theory
- All lifeforms have one or more cells
- The cell is the most simple unit of life
- All cells come from other cells
Modern cell theory
All life is composed of one or more cells, where cells are the basic structural, functional, and organizational unit of life. Moreover, it says all cells come from pre-existing, living cells via cell
division.
The cell theory does not apply to ______ because they are not living cells.
viruses
Says that information flows from DNA to RNA to proteins. In other words, RNA is made from DNA, and proteins are made from RNA.
Central dogma of genetics
The main implication of the central dogma of genetics is that information cannot
travel from _______________, or from __________________.
protein to protein; proteins to nucleic acids
There is a particular case where information can travel from protein to protein. _________ are misfolded proteins that cause other proteins to misfold as well, destroying their function in the process.
Prions
RNA world hypothesis
says that the Earth’s “primordial soup” had a lot of RNA nucleoside triphosphates, which made phosphodiester bonds with each other to create short strands of RNAs. As the strands grew longer and longer, they became more and more stable.
- RNA can store genetic information like DNA
- RNA can catalyze chemical reactions like proteins
