Bio quiz #2
Explain how water's cohesion and adhesion contribute to the movement of water from the roots to the leaves of a tree.
- Adhesion of water to cell walls by hydrogen bonds helps counter the downward pull of gravity. - Cohesion due to hydrogen bonds between water molecules helps hold together the column of water within the cells. - Evaporation from leaves pulls water upward from the roots through water-conducting cells
Methyl group
A chemical group consisting of a carbon atom bonded to three hydrogen atoms. (nonpolar)
Hydroxyl group
A functional group consisting of a hydrogen atom bonded to an oxygen atom by a polar covalent bond. Molecules possessing this group are soluble in water and are called alcohols.
Phosphate group
A functional group consisting of a phosphorus atom covalently bonded to four oxygen atoms (helps transfer energy)
Sulfhydryl group
A functional group consisting of a sulfur atom bonded to a hydrogen atom.
Carbonyl group
A functional group present in aldehydes and ketones and consisting of a carbon atom double-bonded to an oxygen atom. (sugars)
List the major components of a nucleotide and describe how these monomers are linked together to form a nucleic acid.
A nucleotide is made of a nitrogenous base, a pentose sugar, and a phosphate group. These are joined by covalent bonds between a phosphate group on the 5' side and an OH/Hydroxyl group on the 3' side.
Distinguish between a pyrimidine and a purine and ribose and deoxyribose.
A pyrimidine is a six-membered ring of carbon and nitrogen atoms, while a purine is a six-membered ring connected to a five-member ring.
Explain how acids and bases directly or indirectly affect the hydrogen ion concentration of a solution.
Acids increase the hydrogen ion concentration in a substance and bases decrease it.
List and recognize the four major components of an amino acid and explain how amino acids may be grouped according to physical and chemical properties of the side chains.
Amino group, carboxyl group, hydrogen atom, and variable group (represented with R). The r-group is a side chain and amino acids are grouped together by their side chains. The product of these groupings may be hydrophobic or hydrophilic.
● Humans sweat and dogs pant to cool themselves on hot days.
Heat of vaporization
phospholipids
Made of 2 fatty acids and glycerol. Their importance is that they are major cmponents of all cell membranes. They are linked to a pohsphate group.
Describe the characteristics that distinguish nucleic acids from the other major groups of macromolecules.
Nucleic acids (DNA and RNA) store information relating to amino acid sequences of other proteins. Made of nucleotides, which consist of a nitrogenous base, a pentose sugar, and a phosphate group.
Summarize the functions of nucleic acids.
Nucleic acids contain information for all other cell functions and for their own replication.
Explain how organic polymers contribute to biological diversity.
Polymers make up DNA and proteins, so any variation in polymers will vary DNA and proteins, as well.
monosaccharides
Single (simple) sugar molecules
Explain the basis for the pH scale.
The basis for the pH scale is the amount of H+ and OH- ions in a solution. More H+ ions means a solution is more acidic, while more OH- ions means the solution is more basic. 1-14 1-6 Acidic Ex.: Lemon juice 7 Neutral Ex.: Pure water 8-14: Basic Ex.: Oven cleaner
Explain the relationship between the polar nature of water and its ability to form hydrogen bonds.
The charged regions in a water molecule are due to its polar covalent bonds. Oppositely charged regions of neighboring water molecules are attracted to each other, forming hydrogen bonds. Each molecule can hydrogen-bond to multiple partners, and these associations are constantly changing.
Describe the structure and geometry of a water molecule and explain what properties emerge as a result of this structure.
The connections between the atoms of a water molecule are polar covalent bonds. The unequal sharing of electrons and water's V-like shape make it a polar molecule, meaning that its overall charge is unevenly distributed: The oxygen region of the molecule has two partial negative charges, and each hydrogen has a partial positive charge. Four emergent properties of water that contribute to Earth's suitability as an environment for life: cohesive behavior, ability to moderate temperature, expansion upon freezing, and versatility as a solvent.
List the functions of a nucleotide.
The function of a nucleotide is to contain information that, when connected to other nucleotides, provides genetic information to be produced in proteins and all other cells as well as its own replication.
Monomers
The repeating units that serve as the building blocks of a polymer
Explain what distinguishes lipids from other major classes of macromolecules.
These do not included polymers and they have little or no affinity for water. Consist of hydrocarbons. Highly varied in form and function.
● Coastal areas have milder climates than adjacent inland areas.
Water's High Specific Heat
● Ocean temperatures fluctuate much less than air temperatures on land.
Water's High Specific Heat
Explain how a peptide bond forms between two amino acids.
When 2 amino acids are positioned so the carboxyl group of one is adjacent to the amino group of another, they join by dehydration reaction through the removal of a water molecule, this is called a peptide bond.
condensation reaction
a chemical reaction in which two or more molecules combine to produce water or another simple molecule
● Ice floats on water.
because water expands as it freezes; ice is less dense than water
List the four major classes of macromolecules.
carbohydrates, lipids, proteins, nucleic acids
structural isomers
differ in the covalent arrangements of their atoms
Enantiomers isomers
isomers that are mirror images of each other
Explain how water contributes to the fitness of the environment to support life.
water helps moderate Earth's climate & is a solvent for molecules to interact
● If you slightly overfill a water glass, the water will form a convex surface above the top of the glass.
Cohesion
List five characteristics of water that are emergent properties resulting from hydrogen bonding.
Cohesion Adhesion Surface Tension High Specific Heat High Heat of Vaporization OR - Cohesion - High heat capacity - Expands upon freezing - Versatile solvent
Briefly describe the 3D structure of DNA.
DNA forms a double helix between 2 strands of a sugar-phosphate backbone and attracted Nitrogenous bases. In DNA, T and A, and G and C are attracted to each other. While in RNA, T is replaced by U.
Define denaturation and explain how proteins may be denatured.
Denaturation occurs when a protein becomes biologically inactive due to changes in pH, salt concentration, temperature, and other environmental factors.
Describe the important biological functions of polysaccharides.
Polysaccharides are macromolecules (polymers with hundreds of monosaccharides joined by glycosidic linkages.) Every living thing uses polysaccharides for fuel or structure.
Explain how the primary structure of a protein is determined.
Primary structure is simply the sequence of amino acids in a polypeptide. Determined by inherited genetic information.
name the principal energy storage molecules of plants and animals.
fat- animals starch- plants
saturated fats
fats that are solid at room temperature; The hydrocarbon chains of their fatty acids—the "tails" of the fat molecules—lack double bonds, and their flexibility allows the fat molecules to pack together tightly
unsaturated fats
fats that remain liquid at room temperature; The kinks where the cis double bonds are located prevent the molecules from packing together closely enough to solidify at room temperature.
Adhesion
force of attraction between different kinds of molecules
geometric isomers (cis-trans)
have covalent bonds to the same atoms, but these atoms differ in their spatial arrangements due to the inflexibility of double bonds.
Major functional groups
hydroxyl, carbonyl, carboxyl, amino, sulfhydryl, phosphate, methyl
fats
made from glycerol and 3 fatty acids. Structure is made through an ester linkage. The biological importance is that fat stores energy.
steroids
made of four fused rings. Their structure is a carbon skeleton. The importance is the managing of hormones.
Describe the two types of secondary protein structure and explain the roles of hydrogen bonds in maintaining the structure.
- Alphahelix and Beta pleated sheets - Hydrogen bonding is between the carboxyl oxygen of one amino acid and the amino hydrogen of another.large number of hydrogen bonds makes them highly stable. As a result, they increase the stability of the molecule as a whole and help define its shape. Supports a particular shape for that part of the protein.
Using the bicarbonate buffer system as an example, explain how buffers work.
- Buffers: Substances that minimize change in H+ and OH- concentration in a substance. - Buffers usually maintain blood at 7.4.
Explain how carbon skeletons may vary, and explain how this variation contributes to the diversity and complexity of organic molecules.
- Carbon chains form the skeletons of most organic molecules. The skeletons vary in length and may be straight, branched, or arranged in closed rings - Some carbon skeletons have double bonds, which vary in number and location. Such variation in carbon skeletons is one important source of the molecular complexity and diversity that characterize living matter
Explain how carbon's electron configuration determines the kinds and number of bonds carbon will form.
- Carbon has 6 electrons, with 2 in the first electron shell and 4 in the second shell; thus, it has 4 valence electrons in a shell that can hold up to 8 electrons. - Each carbon atom acts as an intersection point from which a molecule can branch off in as many as four directions. This enables carbon to form large, complex molecules.
Describe an ester linkage and how it is formed.
- In making a fat, each fatty acid molecule is joined to glycerol by a dehydration reaction; - a bond between a hydroxyl group and a carboxyl group
Explain how water's high specific heat, high heat of vaporization and expansion upon freezing affect both aquatic and terrestrial ecosystems.
- moderate temperature fluctuations on Earth, creating a favorable environment for life - (evaporation) cooling plants and people off with rain
Carboxyl group
A functional group present in organic acids and consisting of a single carbon atom double-bonded to an oxygen atom and also bonded to a hydroxyl group. (amino acids, fatty acids, vitamins)
Amino group
A functional group that consists of a nitrogen atom bonded to two hydrogen atoms (act like a base)
Cohesion
Attraction between molecules of the same substance
Explain how weak interactions and disulfide bridges contribute to tertiary protein structure.
Attractions between R groups contribute to bends in tertiary structure, and strong bonds called disulfide bridges reinforce the proteins conformation.
Explain how the polarity of the water molecule makes it a versatile solvent.
Because of hydrogen bonding. Positive hydrogen atoms of the water molecule attach and dissolve the negative atoms of other molecules, while the negative oxygen atoms attach and dissolve the positive atoms of other molecules.
● If you place a paper towel so that it touches spilled water, the towel will draw in the water.
Capillary Action (adhesion)
Describe the distinguishing characteristics of carbohydrates and explain how they are classified.
Carbohydrates include both sugars and polymers of sugars. They are classified into Monosaccharides, (single sugars) Disaccharides, (two monosaccharides joined by condensation) and Polysaccharides (polymers of many sugars)
polysaccharides
Carbohydrates that are made up of more than two monosaccharides
disaccharides
Carbohydrates that are made up of two monosaccharides
Explain what determines protein conformation and why it is important.
Protein conformation depends on the physical and chemical conditions of the protein's environment. If things in the protein's environment are altered it goes through a process called denaturation in which the protein unravels and loses it's native shape. When this happens, it becomes biologically inactive.
Distinguish between a protein and a polypeptide.
Protein: consists of one or more polypeptides folded and coiled into specific conformations.Polypeptides: polymers of amino acids.
Describe the characteristics that distinguish proteins from the other major classes of macromolecules and explain the biologically important functions of this group.
Proteins make up over 50% of dry mass of most cells, important in every aspect of an organism. Serve for structural support, storage, transport, cellular communications, movement, and defense against foreign substances.
Using collagen and hemoglobin as examples describe quaternary protein structure.
Quaternary protein structure differs between proteins. In collagen, 3 polypeptides combine in a rope-like structure. Meanwhile, hemoglobin, made of 4 polypeptides, forms a globular structure.
Distinguish between the glycosidic linkages found in starch and cellulose and explain why the difference is biologically important.
Starch has linkages with alpha glucose monomers. Cellulose has linkages with beta glucose monomers, which make every other glucose monomers "upside down." This makes the formation straight and very strong. Humans enzymes don't recognize the beta linkage so we cannot break up cellulose (fiber) and digest it.
● Insects like water striders can walk on the surface of a pond without breaking the surface.
Surface Tension
hydrolysis reactions
a chemical reaction that utilizes water to break apart molecules
Polymers
a long molecule consisting of many similar or identical building blocks linked by covalent bonds; makes up macromolecules