Biology 121 Quiz 1

Where is the DNA in a prokaryotic cell?

in an unbound region called the nucleoid

Which of the following best describes the molecule shown below?

Nucleotide

Links create sugar phosphate "backbone" witha nitrogenous bases as what?

appendages

Each duplicated chromosome has two sister chromatids that?

Will separate during cells division.

What is a nucleotide triphosphate?

Each nucleotide that is added to a growing DNA strand.

Which of the following is unique to the lagging strand in DNA synthesis?

Okazaki fragments

What did Watson and Crick note?

specific base pairing suggested a possible copying mechanism for genetic material

monomer of lipids

fatty acids

What is known as the universal solvent?

Water

Where is the DNA in a eukaryotic cell?

nucleus

Do eukaryotic cells have membrane bound organelles?

yes

Does the antiparallel structure of the double helix affect replication?

yes

Which of the following is broken when water evaporates?

Hydrogen bonds

In what year did James Watson and Francis Crick introduced the double-helical model for the structure of deoxyribonucleic acid, or DNA

1953

Thymine makes up 28% of the nucleotides in a sample of (double stranded) DNA from an organism-Appoximately what percentage of nuceotides in the sample will be guanine?

22%

How many genes in a molecule of DNA?

46 chromosomes, so 23 pairs of chromosomes

Cells are surrounded by water and made up of about how much water

70-95%

What is each chromosome?

A complex of DNA and protein called chromatin

What do nitrogenous bases form complementary hydrogen bonds?

A is with T(U), G is with C

A cell that lacks membrane-bound organelles and that has a circular chromosome is which of the following.

A prokaryotic cell

What is the lagging strand synthesized with?

A series of short fragments called Okazaki fragments which are joined together by DNA Ligase.

In an analysis of nucleotide composition of a molecule of DNA, which of the following combinations of base pairs will be found?

A+C=G+T

DNA is considered a self replicating molecule because?

All of the information necessary to replicate the DNA is contained within the DNA molecule itself. (i.e. the DNA contains the sequence and genes to make Helicase, etc)

What is primase?

An enzyme that can start an RNA chain from scratch

The structure of a biological marcomolecaules consists mostly of atoms linked together by bonds

Carbon, covalent

What is the simplest collection matter that can live?

Cells

What is the cellular basis of life?

Cells contain the necessary components for DNA replication.

Which of the following best describes the actions during Prophase?

Chromosomes condense and the nuclear enevelope breaks down.

Which of the following best describes the actions during Metaphase?

Chromsomes align to ensure proper seperation.

What 4 properties of water support life

Cohesive behavior Ability to moderate temperature expansion upon freezing versatility as a solvent

Okazai fragments are combined by which of the following enyzmes?

DNA Ligase

Which of the following enzymes is directly responsible for synthesizing a new DNA strand in a 5' -3' direction? (Which catalyzes the addition of new nucleotides)

DNA Polymerase

What is the molecular base of life?

DNA as a self-replicating molecule

Which of the following is INACCURATE and NOT a reason why DNA is present in all living things on earth?

DNA is more polar than RNA

Along one template strand of DNA, the leading strand

DNA polymerase can synthesize a complementary strand continuously, moving toward the replication fork.

What enzyme catalyzes the elongation of new DNA at a replication fork?

DNA polymerases

Which of the following would be the most convincing evidence of life on another planet?

Discovery of a molecule on an other planet that is capable of self-replication

Watson and Crick, who discovered the double helical structure of DNA, wrote this structure revealed the possible mechanisms for replication. Why was this so?

Each strand of the double helix contained all the information necessary to make the other strand. The structure of a molecule corresponds to its function, so learning what a molecule looks like can provide insight into what the molecule does.

Which is bigger prokaryotic or eukaryotic cells?

Eukaryotic

What chromosome may have hundreds or even thousands of origins of replication?

Eukaryotic Chromosome

Who had concluded that DNA has two antiparallel sugar-phosphate backbones, with the nitrogenous bases paired in the molecule's interior

Franklin

The three stages of interphase?

G1, S, G2

What are purines?

Have a 6 membered ring fused toa five membered ring Adenine (A) and Guanine (G)

What are pyrimidines?

Have a single 6-membered ring of cytosine, thymine, uracil.

Which enzyme or protein is neccessary for unwinding DNA and forming the replication fork?

Helicase

What is the relationship between structure and function?

Is to manifest in the double helix.

Which of the following is true regarding DNA polymerase?

It builds a DNA polymer that is complementary to a template strand.

What is RNA primer?

It is the initial nucleotide strand that is a short one

What is DNA ligase?

Joins the 3' end of the DNA that replaces the primer to the rest of the leading strand and also joins lagging strand fragments

Which of the following are features that can be found in Animal Cells?

Mitochondria, Plasma membrane, nucleus, ribsomes.

Which of the following are common in all nucleotides?

Nitrogenous base, 5-carbon sugar, phosphate group

If life exists on other planet's, it must

None of the other answers are correct

Monomer of Nucleic acids (DNA/RNA)

Nucleotide (adenine)

How many primers are needed for synthesis?

Only one primer is needed to synthesize the leading strand, but for the lagging strand each Okazaki fragment must be primed separately

A nucleotide consists of a central Nitrogenous base, which connects on the 5' end to a and on the 1' carbon to a

Phosphate group, ribosome sugar

What is DNA polymerase I?

Removes primer from the 5' ends of the leading strand and Okazaki fragments, replacing primer with DNA and adding to adjacent 3' ends

Where does DNA replication begin?

Replication begins at a special sites called the origins of replication, where the two DNA strands are separated, opening up a replication "bubble"

Where does replication proceed?

Replication proceeds in both directions from each origin, until the molecule is copied.

What do multicellar organisms depend on cell division for?

Reproduction, Growth and development, and tissue renewal

What mechanism best describes the replication of DNA?

Semi conservative

Which best describes two identical DNA double helix molecules that result from DNA replication?

Sister chromatids

Which of the following best describes the actions during Anaphase

Sister chromatids are pulled to opposite ends of the cell.

In E Coli, there is a mutation in a gene called dnaB that alters the helicase that normally acts at the origin. Which of the following would you expect as a result of this mutation?

The DNA strands at the origin of replication will separate, but replication will not progress.

DNA is replicated then?

The chromosomes condense

In an unicellular organisms division of one produces?

The entire organism

What is the centromere?

The narrow "waist" of the duplicated chromosome, where the two chromatids are closely attached.

Which of the following best describes the actions during Telophase?

The nucleus reforms around separated chromosomes.

What happens in the DNA double helix?

The two backbones run in opposite 5' 3' directions from each other, arrangement referred to as antiparallel

Can DNA polymerases initiate synthesis of a polynucleotide?

They can only add nucleotides to the 3' end, they can't initiate synthesis of a polynucleotide.

Why do chromosomes condense during mitosis?

To allow the chromosomes to move without becoming entangled and breaking

What does the lagging strand do?

To elongate the other new strand, called the lagging strand, DNA polymerase must work in the direction away from the replication fork

True or False: Adjacent nucleotides are joined by covalent bonds that form between the -OH group on the 3' carbon of one nucleotide and the phosphate group on the 5' carbon on the next

True

A DNA molecule has what?

Two polynucleotides spiraling around an imaginary axis, forming a double helix.

Which of the following is a major difference between RNA and DNA?

Type of sugar

The sequence of bases along a DNA or mRNA polymer are?

Unique for each gene

What is helicase?

Untwists the double helix and separates the template strands at the replication fork

The abundance of which substance is part of why Earth is so habitable?

Water

What is the biological medium on Earth?

Water

What substance do all living organisms require the most?

Water

Which of the following are proerties of water that account to sustain life on Earth?

Water expands upon freezing allowing life to thrive in water even in frigid environments. Water dissolves biological macromolecules such as nucleic acids, proteins, and carbohydrates. Water molecules stick to one another through electrostatic interactions called hydrogen bonds.

Do DNA polymerases add nucleotides only to the free 3' end of a growing strand; therfore, a new DNA strand can elongate only in the 5' to 3' direction

Yes

Does carrying out cellular metabolism set limits on the size of cells?

Yes

monomer of protiens are

amino acids

What are single strand binding proteins?

bind to and stabilize single-stranded DNA until it can be used as a template

Astrobiologists search outer space for signs of life referred to as...

biosignatures

What is interphase?

cell growth and copying of chromosomes in preparation for cell division

What are all organisms made out of?

cells

What is DNA polymerase III?

continuously synthesizes the leading strand and elongates Okazaki fragments

What is the sugar in DNA?

deoxyribose (2'C has -H)

What is Topoisomerase?

it corrects "overwinding" ahead of replication forks by breaking, swiveling, and rejoining DNA strands

What do prokaryotic cells lack?

membrane bound organelles

Nucleoside=

nitrogenous base + sugar

Which of the following typically describes two carbon atoms sharing electrons, such as those found within a nitrogenous base?

non polar covalent bonds

All cells have

plasma membrane, semifluid cytosol, chromosomes, ribosomes

What are nucleic acids?

polymers of nucleotides or polynucleotides

what are the two families of nitrogenous bases?

pyrimidines and purines

What is the sugar in RNA?

ribose sugar (2'C had -OH)

monomer of carbohydrates

sugar (glucose)

What is primase?

synthesizes an RNA primer at 5' end of leading strand and at 5' end of each Okazaki fragment of lagging strand

What is the continuity of life based on?

the reproduction of cells, or cell division

Which of the following best describes DNA?

two complementary nucleic acid polymers, running in opposite directions, held together by hydrogen bonds