High School Biology : Understanding Chromosomes and Genes

Study concepts, example questions & explanations for High School Biology

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Example Questions

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Example Question #1 : Understanding Chromosomes And Genes

Which of the following is/are example(s) of nucleic acids?

Possible Answers:

DNA

Cholesterol

Glucose

Two of these answers are correct

rRNA

Correct answer:

Two of these answers are correct

Explanation:

Nucleic acids include DNA and all forms of RNA (mRNA, tRNA, rRNA, and htRNA). Note that the different types of RNA have the same base structure, but serve different functions. Messgener RNA (mRNA) is used as the template for protein translation. Transfer RNA (tRNA) transports amino acid residues to the ribosome during translation to aid in polypeptide elongation. Ribosomal RNA (rRNA) is used to form the structure of the ribosomal subunits. Heternuclear RNA (htRNA) is the original product of transcription, and is found in the nucleus prior to post-transcriptional modifications.

Glucose is a carbohydrate, and cholesterol is a lipid.

Example Question #412 : High School Biology

The correct pairing of nucleotide bases in DNA are __________.

Possible Answers:

cytosine with guanine and adenine with uracil

cytosine with guanine and adenine with thymine

cytosine with adenine and guanine with thymine

cytosine with thymine and guanine with adenine

Correct answer:

cytosine with guanine and adenine with thymine

Explanation:

The nucleotides in DNA always pair the same way; A with T and G with C. This is due to the chemical structure of each base; adenine and thymine form two hydrogen bonds when pairing, and guanine and cytosine form three. The other important thing to remember is that there is a different nitrogen base in RNA called uracil; uracil is not found in DNA, so pay attention to which molecule the question is asking about.

Example Question #2 : Understanding Chromosomes And Genes

Which of the following contains and controls the use of DNA?

Possible Answers:

Cytoplasm

Chromosomes

Chromatin

Nucleus

Genes

Correct answer:

Chromatin

Explanation:

During most of the cell cycle, DNA is found as chromatin. Chromatin is a mass of DNA and associated proteins. Depending on the state and activation of those proteins and on how tighly packed the DNA is around the proteins, certain genes can be turned on or off.

Chromosomes form from condensed chromatin only during mitosis (specifically during prophase), and are absent during most of the cell's cycle. Genes are units of heredity that encode the information needed to specify the amino acid sequence of proteins. The gene is the functional segment of DNA located at a specific place, or locus, on a chromosome. The cytoplasm is the material contained in the cell membrane and outside the nucleus. The nucleus is a membrane-bound organelle that contains the cell's genetic material. 

Example Question #72 : Dna, Rna, And Proteins

Operons __________.

Possible Answers:

are only found in eukaryotes

often involve multiple chromosomes

are always involved in protein synthesis

are sets of genes that are often regulated together

More than one of the other answer choices is correct.

Correct answer:

are sets of genes that are often regulated together

Explanation:

An operon is a segment of DNA that is under the control of a single promoter. For example, if there are three genes required for breaking down a sugar in an operon, they will all be activated together. This makes sense, as there is no sense in activating only one or two of these genes, since all three are required to break down the sugar. For example, the control element that turns on the operator can be the sugar itself. It should make sense that the genes required to break down a sugar are only turned on if that sugar is present.

Example Question #3 : Understanding Chromosomes And Genes

Genes are said to be expressed when they are __________.

Possible Answers:

transcribed and translated

inserted into the ribosome

deleted

copied into another strand of DNA

replicated

Correct answer:

transcribed and translated

Explanation:

Genes are expressed when their gene products are made, to do this transcription and translation must occur to synthesize the protein which is coded for by the DNA.

Example Question #4 : Understanding Chromosomes And Genes

How can synteny help with understanding chromosomes?

Possible Answers:

It can indicate recombination events

It can indicate crossover events

It can indicate conserved regions

It can indicate recessive neofunctionalization 

It can indicate hybridization

Correct answer:

It can indicate conserved regions

Explanation:

Synteny is the conservation of order of genes. Being able to see conserved blocks in genes when comparing two chromosomes of the same species, it indicates that at some time in evolutionary history, these blocks originated from a hypothetical common ancestor. Genes that are highly conserved among species are usually vital to the organism's viability. For example, the genes required for glycolysis to occur are required in almost all organisms.  

Example Question #75 : Dna, Rna, And Proteins

A chromosome is a molecule of __________.        

Possible Answers:

Protein

DNA

Carbohydrate

RNA

Correct answer:

DNA

Explanation:

A chromosome is one molecule of DNA. It contains genetic information required for cell replication and the passing down of genetic information. Humans have 23 pairs of chromosomes, with one chromosome per pair from the mother, and the other from the father.

Example Question #76 : Dna, Rna, And Proteins

A human’s diploid number is 2n=46. What is the haploid number of a human gamete? 

Possible Answers:

Correct answer:

Explanation:

Humans have 23 homologous pairs of chromosomes, which adds up to 46 chromosomes total. Diploid cells have two copies of each chromosome (one from the mother, one from the father). A gamete is haploid, meaning it only contains one copy of each chromosome. The gametes (haploid) will fuse in a process known as fertilization in order to form a diploid zygote.

Example Question #77 : Dna, Rna, And Proteins

Which of the following best describes an allele?

Possible Answers:

A variant form of a gene

A gene locus

Genotype

A gene

Correct answer:

A variant form of a gene

Explanation:

An allele is a variant or alternative form of a gene or gene locus. Humans are diploid—we have two alleles at each genetic locus. One allele is inherited from the mother and one allele comes from the father. Sometimes different alleles can lead to different phenotypic traits (e.g. eye color); however, most genetic variations result in little to no observable variation. An organism is considered homozygous if it possesses two of the same alleles at a particular locus. If the alleles are different, then the organism is considered heterozygous. 

Example Question #78 : Dna, Rna, And Proteins

DNA is found in which of the following?

Possible Answers:

Proteins

Chromosomes

Amino acids

RNA

Correct answer:

Chromosomes

Explanation:

DNA—deoxyribonucleic acid—is found in chromosomes within a cell’s nucleus. A complete set of DNA (i.e. 46 chromosomes) is called a genome. DNA contains instructions that make humans different from other species and other individuals. DNA provides instructions for all the proteins that the body makes and is passed from adults to offspring.  DNA cannot get out of the nucleus; however, RNA can. RNA is used to get the instructions from DNA out of the nucleus and into the site of protein synthesis: the ribosomes within the cytoplasm. Proteins are made of amino acids and determine the structure and function of all of the body’s cells.

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