Biology Exam 2 Study Set

What are the two most common glycosidic linkages?

- α-1,4-glycosidic linkage - β-1,4-glycosidic linkage

. Carbohydrates store and provide chemical energy. We see this in ____________, in which plants harvest energy from sunlight and store it in the bonds of carbohydrates

. Carbohydrates store and provide chemical energy. We see this in Starch, in which plants harvest energy from sunlight and store it in the bonds of carbohydrates

. Provide the complementary strand: 3' ATTTGGCC 5'

5'TAAACCGG3'

Describe deoxyribonucleotides.

A deoxyribonucleotide is a nucleotide that contains deoxyribose. They are the monomeric units of the informational biopolymer, deoxyribonucleic acid (DNA). Each deoxyribonucleotide comprises three parts: a deoxyribose sugar (monosaccharide), a nitrogenous base, and one phosphoryl group.

True or false? Two sugars linked together form a disaccharide.

A disaccharide (also called a double sugar or biose) is the sugar formed when two monosaccharides (simple sugars) are joined by glycosidic linkage. ... The most common types of disaccharides—sucrose, lactose, and maltose—have 12 carbon atoms, with the general formula C12H22O11.

. Phosphodiester linkages form a ____________.

A phosphodiester bond occurs when exactly two of the hydroxyl groups in phosphoric acid react with hydroxyl groups on other molecules to form two ester bonds. An example is found in the linking of two pentose (5 carbon sugar) rings to a phosphate group by strong, covalent ester bonds

RNA's secondary structure results from complementary base pairing: A with ___; G with ___.

A-U G-C

. Starch is hydrolyzed by ____________, which plays a key role in carbohydrate digestion

Amylases play a key role in carbohydrate digestion

3.Carbohydrates have the molecular formula ___________.

CH2O

Carbohydrates have the molecular formula ___________. a. What does "n" represent? b. True or false? "n" cannot vary from 3 to over a thousand.

CH2O - "n" equals the number of "carbon-hydrate groups" - "n" can vary from 3 to over a thousand

Captured energy is used to make ____________.

Captured energy is used to make ATP: (CH2O)n + O2 + ADP +Pi → CO2 + H2O + ATP

What are the functions of carbohydrates?

Carbohydrates have diverse functions in cells: - Serve as energy source to other molecules, such as nucleotides and amino acids - Provide fibrous _________ materials - Indicate cell _________ - Store chemical ________

Carbohydrates play an important role in ____________, ____________, and ____________.

Carbohydrates play an important role in cell structure, cell identity, and energy storage:

Carbohydrates store more energy than CO2. Explain why.

Carbohydrates store more energy than CO2: - Electrons in C == O and C - O bonds are held tightly and have low potential energy - Electrons in C - H and C - C bonds are weaker and have higher potential energy

. ________, __________, and __________ form long strands with bonds between adjacent strands: a. Strands may be organized into fibers or sheets b. Gives cells and organisms strength and elasticity

Cellulose, chitin, and peptidoglycan form long strands with bonds between adjacent strands: a. Strands may be organized into fibers or sheets b. Gives cells and organisms strength and elasticity

. ____________is a structural polymer found in cell walls of ____________and exoskeletons of ___________ and _____________: a) What is the monomer of chitin? b) Chitin's structure is similar to ____________. i. ____________with every other monomer flipped ii. Linear strands with ____________between them

Chitin is a structural polymer found in cell walls of fungi and exoskeletons of insects and crustaceans: - Monomer is N-acetylglucosamine (NAG) - Structure is similar to cellulose: ▪ β-1,4-glycosidic linkages with every other monomer flipped ▪ Linear strands with hydrogen bonds between them

Describe the structure of DNA.

DNA bases pair up with each other, A with T and C with G, to form units called base pairs. Each base is also attached to a sugar molecule and a phosphate molecule. Together, a base, sugar, and phosphate are called a nucleotide. Nucleotides are arranged in two long strands that form a spiral called a double helix.

Fats form by ____________ between a ________________________of glycerol and a ________________________ of a free fatty acid.

Fats form by _________ reactions between: - ________ group of glycerol - _________ group of a free fatty acid • Glycerol and fatty acid molecules become joined by an ___________ linkage • Fatty acids are not linked into chains: - They are not polymers

When RNA folds over what does it form?

Folding roles of RNA RNA molecules play a central role in virtually all cellular processes. To exert their function RNAs have to fold into specific three-dimensional structures. The process of folding describes how an RNA molecule undergoes the transition from the unfolded, disordered state to the native, functional conformation.

Describe RNA's versatility.

Furthermore, RNA can bind several cofactors that are used by protein enzymes to facilitate a wide variety of chemical processes. Despite its limited functional groups, these observations indicate RNA is a versatile molecule that could, in principle, catalyze the myriad reactions necessary to sustain life.

Phosphodiester linkage (bond) occurs between a ____________ on 5′ carbon of one nucleotide and ____________on the 3′ carbon of another.

In DNA and RNA, the phosphodiester bond is the linkage between the 3' carbon atom of one sugar molecule and the 5' carbon atom of another, deoxyribose in DNA and ribose in RNA. ... When a single phosphate or two phosphates known as pyrophosphates break away and catalyze the reaction, the phosphodiester bond is formed.

The backbone is directional, occurring in the ____________.

In a DNA molecule, the two strands are organized in such a way that the DNA backbone of one strand runs in the 5'-to-3' direction, whereas the DNA backbone of the other strand runs in the 3'-to-5' direction; therefore, the two strands are antiparallel to each other.

Lipids do not possess shared chemical structure. Explain why. Name three important types of lipids that are found in cells.

Lipid do not possess shared chemical structure: - Structure varies widely - Hydrocarbon skeleton can be put together in many different ways

How do monosaccharides vary?

Monosaccharides can differ from one another in three ways: (1) the location of their carbonyl group; (2) the number of carbon atoms they contain; and (3) the orientations of their hydroxyl groups.

β-1,4-glycosidic linkages are not easy to hydrolyze. Explain why.

Most organisms lack enzymes to hydrolyze them - These fibers are resistant to water, making hydrolysis difficult

Describe the two groups of nitrogenous bases

Nitrogenous bases present in the DNA can be grouped into two categories: purines (Adenine (A) and Guanine (G)), and pyrimidine (Cytosine (C) and Thymine (T)). These nitrogenous bases are attached to C1' of deoxyribose through a glycosidic bond. Deoxyribose attached to a nitrogenous base is called a nucleoside.

What is a nucleic acid? What are the components of a nucleic acid?

Nucleic acids are polymers of individual nucleotide monomers. Each nucleotide is composed of three parts: a 5-carbon sugar, a phosphate group, and a nitrogenous group.

____________is a structural polymer found in ____________cell walls: a. Long backbones of ____________monosaccharides b. Joined by ____________ c. Short amino acid chains form ____________between adjacent strands

Peptidoglycan is a structural polymer found in bacterial cell walls: - Long backbones of alternating monosaccharides - Joined by β-1,4-glycosidic linkages - Short _amino chains form peptide bonds between adjacent strands

Plants store sugar as ____________: a. Composed of ____________ b. Forms a ____________ c. Amylose—____________starch with ____________ d. Amylopectin—____________starch with some ____________ e. Branches occur about once in every ____________

Plants store sugar as STARCH : a. Composed of polysaccharides b. Forms a a 1,4 linkage (Helix) c. Amylose—starch with alpha (1-4) glyosidic bonds d. Amylopectin— branched starch with some a a-1,6-glycosidic linkages e. Branches occur about once in every 30 monomers

Nucleic acids polymerize via?

Polymerization of Nucleotides (Phosphodiester Bonds) Nucleotides are joined together similarly to other biological molecules, by a condensation reaction that releases a small, stable molecule. ... The 3' hydroxyl group forms a bond to the phosphorus atom of the free nucleotide closest to the 5' oxygen atom.

Why are sugars important?

Provide chemical energy in cells - Serve as building blocks for larger compounds

Bases of RNA typically form hydrogen bonds with complementary bases on the ____________.

RNA can temporarily form hydrogen bonds between bases of two strands.

Describe the primary structure of RNA.

RNA consists of ribose nucleotides (nitrogenous bases appended to a ribose sugar) attached by phosphodiester bonds, forming strands of varying lengths. The nitrogenous bases in RNA are adenine, guanine, cytosine, and uracil, which replaces thymine in DNA.

What are the three steps of DNA replication?

Replication occurs in three major steps: the opening of the double helix and separation of the DNA strands, the priming of the template strand, and the assembly of the new DNA segment. During separation, the two strands of the DNA double helix uncoil at a specific location called the origin.

Saturation changes physical state • Foods that contain ____________with ____________ are said to be healthier • Saturated lipids ▪ Highly saturated lipids are ____________at room temperature ▪ Saturated lipids with ________________________are ____________ at room temperature ▪ ____________unsaturated lipids are ____________at room temperature

Saturation changes physical state: - Foods that contain lipids with double bonds said to be healthier - Saturated lipids: ▪ Highly saturated lipids are _________ at room temperature ▪ Saturated lipids with long hydrocarbon tails are stiff solids at room temperature - Highly unsaturated lipids are ________ at room temperature

Starch and glycogen are easily hydrolyzed because they have ____________.

Starch and glycogen are easily hydrolyzed because they have α-glycosidic linkages

____________is a structural polymer: a) The ____________ is the major component of the protective layer around plant cells b) Made ____________ joined by ____________ c) Every other glucose is flipped. As a result, this

Starch is a structural polymer: - Major component of the protective layer around plant cells called the cell wall - Made of D-glucose monomers joined by β-1,4 - glyosidic linkages - Every other glucose is flipped, so it: ▪ Generates a linear molecule rather than a helix ▪ Permits hydrogen bonds to form between adjacent, parallel strands

Name 5 examples of polysaccharides.

Starch, glycogen, cellulose, Chitin, Peptidoglycan

Stored in ____________and ____________ b. Can be broken into glucose monomers for ____________ c. Highly branched ____________, nearly identical to ____________ d. Branches occur in about ____________

Stored in liver and muscle cells - Can be broken into glucose monomers for energy - Highly branched α-glucose polymer, nearly identical to starch: ▪ Branches occur in about 1 out of 10 monomers

True or false? Sugars are linked when a condensation reaction occurs between three hydroxyl groups.

Sugars are linked when a condensation reaction occurs between two hydroxyl groups

What is the significance of Watson and Crick's model?

The discovery in 1953 of the double helix, the twisted-ladder structure of deoxyribonucleic acid (DNA), by James Watson and Francis Crick marked a milestone in the history of science and gave rise to modern molecular biology, which is largely concerned with understanding how genes control the chemical processes within cells.

The energy in ____________is used to drive other reactions, such as polymerization and muscle movement

The energy in ATP is used to drive other reactions, such as polymerization and muscle movement

Define fatty acid.

The most basic unit of lipids, composed of triglycerides and phospholipids

Explain how DNA's double helix is highly structured?

The nitrogenous bases are stacked in the interior in pairs, like the steps of a staircase; the pairs are bound to each other by hydrogen bonds. The two strands of the helix run in opposite directions, so that the 5′ carbon end of one strand faces the 3′ carbon end of its matching strand.

Define isoprenoid.

The terpenoids, sometimes called isoprenoids, are a large and diverse class of naturally occurring organic chemicals derived from the 5-carbon compound isoprene, and the isoprene polymers called terpenes.

What is the difference between saturated hydrocarbon chains and unsaturated hydrocarbon chains?

They can be straight chain, branched chain or cyclic molecules. The difference between saturated and unsaturated hydrocarbons is that saturated hydrocarbons contain only single bonds between atoms while unsaturated hydrocarbons contain double or triple bonds between the atoms.

True or false? Phosphate group and nitrogenous base are bonded to sugar molecule.

This is actually false. In a nucleotide, the phosphate group will attach to the ribose (or deoxyribose) sugar, not the nitrogenous base.

True or false? Ribose and deoxyribose have an -OH group bonded to 3' carbon.

True

True or false? Carbohydrates contain a carbonyl group, hydroxyl groups, and many carbon-hydrogen bonds.

True, Contain a carbonyl group (C == O), hydroxyl groups (-OH), and many carbon-hydrogen bonds (C - H)

True or false? Ribonucleotides are monomers of RNA, have ribose as their sugar, and has an -OH group bonded to the 1' carbon.

True, yes the -OH group attached to the 1' carbon group.

28. When a cell needs energy, it breaks down ____________.

When a cell needs energy, it breaks down glucose

What are fats? What is the primary role of fats?

_________: - Composed of three fatty acids linked to _________ - Also called triacylglycerols or triglycerides • The primary role of fats is __________ storage: - Large number of high-energy bonds in fatty acid chains - Bonds allow fats to store twice as much chemical energy

What are steroids? Provide several examples.

____________: - Family of lipids - Distinguished by bulky, _________ structure - Differ from one another by ___________ groups attached to carbons in rings • Examples: - Hormones estrogen and testosterone - Cholesterol, component of plasma membranes

James Watson and Francis Crick determined?

a. Two strands are held together by hydrogen bonds between pyrimidines and purines b. Complementary base pairing (Watson-Crick pairing) occurs between A and T, C and G c. DNA strands are antiparallel d. Antiparallel strands predicted to twist together to form double helix

What are lipids?

fats, oils, waxes

Animals store sugar as ____________:

glycogen

What is a polysaccharide?

many sugars

Define the following: a. Monosaccharide: b. Polysaccharide: c. Oligosaccharide:

monosaccharide ("one-sugar") monomers - oligosaccharide ("few-sugars") small polymers - polysaccharide ("many-sugars") large polymers

What are hydrocarbons?

organic molecules consisting of only carbon and hydrogen

What determines the primary structure of RNA?

the sequence of ribonucleotides

Two sugar-phosphate strands are

​Phosphate Backbone DNA consists of two strands that wind around each other like a twisted ladder. Each strand has a backbone made of alternating sugar (deoxyribose) and phosphate groups. Attached to each sugar is one of four bases--adenine(A),cytosine(C), guanine (G), or thymine (T).

Both glyosidic linkages are between?

• Both linkages are between the C-1 and C-4 carbons

How do carbohydrates indicate cell identity? How are glycoproteins and glycolipids involved?

• Display information on the outer surface of cells: - Glycoproteins—proteins with attached carbohydrates - Glycolipids —lipids with attached carbohydrates • Glycoproteins and glycolipids are key molecules in: - Cell-cell recognition: Identify cells as "self" - Cell-cell signaling: Communication between cells

Glycogen is hydrolyzed by the enzyme ____________: a. Many animal cells contain ____________ b. They can break down ____________to provide ____________

• Glycogen is hydrolyzed by the enzyme Glycogen phosphorylase: - Many animal cells contain phosphorylase - They can break down glycogen to provide glucose

1.____________, or ____________, separates life from non-life: • Serves as a ________________________: ▪ Allows entry of materials needed by cell ▪ Keeps damaging materials out of cell • Facilitates chemical reactions necessary for life: ▪ Allows chemical reactions to occur by sequestering appropriate chemicals

• Plasma membrane, or cell membrane, separates life from nonlife: - Serves as _____________barrier: ▪ Allows entry of materials needed by cell ▪ Keeps damaging materials out of cell - Facilitates chemical reactions necessary for life: ▪ Allows chemical reactions to occur by sequestering appropriate chemicals

Glycosidic linkages are broken by ____________.

• The linkages can be broken by hydrolysis reactions