3 - STAAR Review

What is the role of mRNA in expressing specialized structures?

• Making energy available for cellular activities

• Creating bonds to form biomolecules

• Producing sugars that assist with replication

• Providing information to form proteins

From a single fertilized ovum undergoing a series of rapid cell divisions, a human infant develops. The embryonic cells become specialized for a variety of functions. Which of these statements best describes how different cell types develop?

• Each cell type contains only the active parts of the DNA needed for that cell type.

• Each cell type has only one chromosome containing the DNA needed for that cell type.

• Each cell has an identical copy of DNA with enzymes controlling the expression of specific genes, leading to a variety of cells.

• Each cell has multiple copies of DNA that are affected in different ways by the environment to change the function of the cell at regular intervals.  

Each strand of a DNA molecule contains nitrogenous bases that pair with other nitrogenous bases in very specific ways. A diagram of a section of DNA is shown. Which DNA strand is complementary to the one shown above?

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• 
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The sequence of nitrogenous bases in DNA varies widely. The sequence of the bases in DNA is most important for which of the following?

• Providing the instructions for the traits of an organism

• Preventing mutations from occurring during DNA replication

• Allowing the DNA to have the shape necessary for replication

• Helping form the sugar-phosphate backbone of DNA molecules

Which part of a DNA molecule is responsible for the direct coding of specific traits in an organism?

• The number of hydrogen bonds that hold the strands of DNA together.

• The number of carbons in the DNA molecule.

• The sequence of nucleotide bases in the DNA molecule.

• The sequences of phosphates along each DNA strand.

A segment of DNA is shown in the diagram. Which of these identifies is the part of the DNA segment labeled "X"?

• Nucleotide

• Phosphate Group

• Hydrogen Bond

• Deoxyribose

Which property is shared by the cells of all living things?

• The cells contain DNA composed of adenine, thymine, guanine and cytosine

• The cells surrounded by a phospholipid bilayer and a cell wall made of cellulose

• The cells have chromosomes that are located inside a membrane-bound nucleus

• The cells rely on mitochondria to carry out aerobic cellular respiration

Researchers combined sequences of fruit-fly DNA from a gene for a particular trait with frog

DNA. The mixture was heated to separate the DNA strands. Cooling allowed the single strands

to form pairs. The researchers observed that some of the fruit-fly DNA paired with frog DNA. The results provide evidence that —

• similar nucleotides are present in both fruit-fly and frog DNA

• fruit flies and frogs can be made to develop some of the same physical traits

• heat can cause mutations in the DNA sequences of organisms

• the replication of genetic material can occur at any temperature

A partial DNA segment and a mRNA codon chart are shown. What amino acid sequence is encoded in the partial DNA segment?

• Serine - Threonine - Tyrosine

• Serine - Serine - Tyrosine

• Serine - Threonine - Methionine

• Serine - Alanine - Methionine

A model of a biological process is shown. What is the purpose of this process?

 

• To replicate the DNA of an organism before cell division

• To assemble nucleotides in an mRNA chain along a DNA template

• To synthesize amino acids used to unzip strands of DNA and copy the genetic code

• To translate the genetic code into a specific sequence of amino acids