Summer 2015 Cell Biology Ch. 3, 4, 5

Explain why sequencing the human genome will have an impact on medicine

-predictive genetics tests to confirm disposition to medical conditions and diseases -provide insight to medical interventions and procedures to potentially counter the predisposed conditions to improve quality of life and longevity

If adenine makes up 22% of the bases in a given double-stranded DNA molecule, what percentage is made up of guanines?

28% 22*2= 44; 100-44= 56; 56/2= 28

In aerobic cells, the complete oxidation of glucose via glycolysis and the citric acid cycle yields ____ molecules of ATP per molecule of glucose.

38

Like other catalysts, enzymes a. increase the rate of reactions without being consumed in reactions b. shift the chemical equilibrium from more reactants to more products c. do not alter the chemical equilibrium between reactants and products d. both a and c e. both a and b

Both a and c a. increase the rate of reactions without being consumed in reactions c. do not alter the chemical equilibrium between reactants and products

What do you understand by the term metabolism? Give two examples.

Cell metabolism includes the breakdown and synthesis of molecules in order to transport/translate that into a form that can be used. Examples: Catabolic/ breaking down Anabolic/ harvesting food

What is one thing we need from our food and why?

Electrons at the most basic level; glucose to convert to ATP for energy to carry out bodily activity

T/F: Approximately 50 percent of the chemical reactions in cells are catalyzed by enzymes.

False

T/F: DNA synthesis requires the presence of a complementary nucleotide strand, whereas RNA synthesis does not

False

T/F: Gel electrophoresis is used to amplify specific fragments of DNA in vitro.

False

T/F: Meiosis results in a change of nuclear DNA from haploid to diploid.

False

T/F: The human genome has more genes tha plant genomes

False

T/F: Most of the ATP derived from the breakdown of glucose in anaerobic cells is derived from glycolysis.

True

Nitrogen fixation can be carried out by a. a few species of bacteria b. bacteria, fungi, and plants c. plants d. all eukaryotes e. all organisms

a. a few species of bacteria

In eurkaryotic cells, glycolysis takes place in the a. cytosol b. nucleus c. mitochondria d. endoplasmic reticulum e. all of the above

a. cytosol

Which of the following statements about introns is true? a. they are part of a gene, but they are absent from the corresponding mRNA b. they are sequences within genes that are not transcribed c. they make up only a small fraction of the DNA of a mammalian gene d. prokaryotes do not have introns in their genes

a. they are part of a gene, but they are absent from the corresponding mRNA

Fatty acids are broken down in a stepwise process, _____ carbon(s) at a time. a. one b. two c. four d. six e. eight

a. two

Two copies of gene are called _____

alleles

As compared on a per gram basis to carbohydrates, fatty acids produce approximately _____ energy through the oxidation process. a. 50 percent more b. 2.5 times more c. 5 times more d. 10 times more

b. 2.5 times more

The human genome is distributed among a. 48 chromosomes (46 autosomes and 2 sex chromosomes) b. 24 choromosomes (22 autosomes and 2 sex chromosomes) c. 24 chromosomes (23 autosomes and 1 Y chromosome) d. 26 chromosomes (24 autosomes and and 2 sex chromosomes)

b. 24 choromosomes (22 autosomes and 2 sex chromosomes)

In the light reactions of photosynthesis, a. sugars are synthesized from CO2, and water b. H20 is converted to O2 and NAD is reduced to NAPDH c. oxidative phosphorylation produces ATP d. all of the above e. none of the above

b. H20 is converted to 02 and NAD is reduced to NADPH

A reaction in which the substrate glucose binds to the enzyme hexokinase and the configeration of both molecules changes is an example of a. lock-and-key mechanism b. an induced fit mechanism c. competitive inhibition d. allosteric inhibition e. bonding with an intermediate

b. an induced fit mechanism

The function of telomeres is a. to condense the chromosomes in readiness for mitosis b. critical in chromosome replication and maintenance c. to hold the sister chromatids together and bind the spindle during mitosis d. to provide a safe binding site for the DNA polymerase to initiate replication

b. critical in chromosome replication and maintenance

The hydrolysis of ATP and ADP and phosphate allows glucose-6-phosphate to be synthesized from glucose and phosphate because the a. heat produced from ATP hydrolysis drives glucose-6-phosphate to be synthesis b. enzymatic coupling of these two reactions allows the energy of ATP hydrolysis to drive the synthesis of glucose-6-phosphate c. energy of glucose phosphorylation drives ATP splitting d. all of the above

b. enzymatic coupling of these two reactions allows the energy of ATP hydrolysis to drive the synthesis of glucose-6-phosphate

Taq polymerase is used in the polymerase chain reaction because it a. works best in aqueous solution b. is stable at high temperatures c. recognizes specific primer sequences d. can make DNA sequences from RNA sequences e. comes from the sea

b. is stable at high temperatures

During the formation of eggs and sperm, one member of each chromosome pair is transmitted to each cell in a type of cell division called a. mitosis b. meiosis c. cytokinesis d. gametogenisis e. Both a and c

b. meiosis

DNA replicates a. concervitively b. semiconservatively c. liberally d. by hybridization e. by congression

b. semiconservitively

In the nucleus, introns are removed from transcripts by a. restriction nucleases b. splicing c. exonucleases d. endonucleases e. proteases

b. splicing

For humans, _______ essential amino acids must be provided by the diet. a. 0 b. 4 c. 9 d. 18 e. 20

c. 9

Restriction endonucleases are enzymes that a. act only in a single species of bacteria b. act only on the ends of DNA strands c. cleave DNA only at specific sequences d. cleave only nuclear DNA e. are restricted to cleaving RNAs

c. cleave DNA only at specific sequences

The Calvin cycle can occur a. in the absence of CO2 b. only in the presence of light c. in the absence of light d. only in the absence of oxygen e. only in the presence of oxygen

c. in the absence of light

The DNA of eukaryotic cells is wrapped around histones to form structures called: a. nucleoli b. nuclear matrices c. nucleosomes d. centromeres e. centrosomes

c. nucleosomes

A codon is a a. region of DNA coding for one protein b. sequence of three nucleotides on a tRNA that binds to an mRNA c. sequence of three nucleotides on an mRNA that binds to a specific tRNA d. sequence of three nucleotides on the coding strand of DNA e. sequence of a transcript removed in the formation of an mRNA

c. sequence of three nucleotides on an mRNA that binds to specific tRNAs

Coenzymes are a. enzymes in the same pathway b. proteins that form dimeric enzymes c. small molecules that work with an enzyme to enhance reaction rate d. small molecules that allosterically regulate enzymes e. all of the above

c. small molecules that work with an enzyme to enhance reaction rate

The percentage of the human genome that encodes proteins is approximately a. 98.8% b. 20% c. 80% d. 1.2%

d. 1.2%

How many different RNA triplets (codons) specify amino acids? a. 24 b. 36 c. 60 d. 61 e. 64

d. 61

Gluconeogenesis can produce glucose, starting with a. lactate b. pyruvate c. fatty acids d. all of the above e. none of the above

d. all of the above (lactate, pyruvate, fatty acids)

Enzymes act by a. lowering the overall free energy change of the reaction b. decreasing the distance reactants must diffuse to find each other c. increasing the activation energy d. decreasing the activation energy e. both a and d

d. decreasing the activation energy

Under anaerobic conditions, the NADH produced by glycolysis is recycled by a reaction that produces NAD+ and ______. a. ethenol b. lactate c. pyruvate d. ethenol or lactate e. citrate

d. ethanol or lactate

Heterochromatin consists of a. DNA associated with nucleosomes b. 10-nm chromatin fibers c. decondensed, transcriptionally active chromatin d. highly condensed, transcriptionally inactive chromatin e. DNA associated with heterogeneous nuclear RNA

d. highly condensed, transcriptionally inactive chromatin

The end products of anaerobic metabolism of glucose may be any of the following except a. acetaldehyde b. ethanol c. lactate d. methanol

d. methanol

A centromere is defined as a region of the chromosome that a. is located at the ends of the chromosomes and plays a critical role in chromosome replication and maintenance b. is relatively decondensed and distributed throughout the nucleus c. is very highly condensed and resembles the chromatin of cells undergoing mitosis d. plays a critical role in ensuring the correct distribution of duplicated chromosomes to daughter cells during mitosis

d. plays a critical role in ensuring the correct distribution of duplicated chromosomes to daughter cells during mitosis

Because of the central role that one amino acid plays in the mechanism by which proteins are cleaved by the enzymes trypsin and chmotrypsin, these enzymes are called ______ proteases. a. histidine b. lysine c. arginine d. serine e. threonine

d. serine

Which of the following correctly distinguishes the terms "genotype" and "phenotype"? a. the phenotype is the genetic composition of an organism, and the genotype is the physical appearance b. there is no difference between genotype and phenotype c. phenotype is said to be dominant while genotype is said to be recessive d. the genotype is the genetic composition of an organism, whereas the phenotype is the physical appearance

d. the genotype is the genetic composition of an organism, whereas the phenotype is the physical appearance

The chromatin that is decondensed and contains most of the active genes is called ______

euchromatin

ATP is produced in the mitochondria by a process called ____________________

oxidative phosphorylation

The ultimate acceptor of electrons from the electron transport chain is ______

oxygen

_______ are circular DNA found inside bacteria that confer some specific traits such as antibiotic resistance

retroviruses

In addition to mRNA, the two types of RNA necessary for protein synthesis are _____ and _____.

tRNA, rRNA

The enzyme that replicates the sequences at the end of the eukaryotic chromosomes is called ______

telomerase

What is the definition of allosteric regulation?

the regulation of a protein by binding an effector molecule at a site other than the protein's active site