MCAS Guide Pages 7-8

DNA StructureRNA

DNA & RNA activities

DNA

• Shape is a double helix• Each “step” of the helix is made by two connected

nucleotides (monomer for nucelic acid)• Each nucleotide has a sugar, phosphate and base• There are 4 different bases that make pairs

: A—T; and C—G

DNA vs RNA

• Both are Nucleic Acids• DNA has sugar Deoxyribose / RNA has sugar Ribose• DNA has bases A, T, C, G / RNA has bases A, U, C, G• DNA is always in the nucleus / RNA goes from

nucleus to ribosomes• DNA has 2 strands (double helix) / RNA has 1 strand

How DNA is used

• DNA replication – a copy of DNA is made, in the nucleus, before mitosis (cell division)

• Gene Expression– Transcription – A copy of RNA is written from

DNA, in the nucleus, so information can be brought to ribosome.

– Translation – Proteins are made, in the ribosomes, to build body parts (muscles, enzymes etc)

Which of the following statements describes a DNA molecule?

A. It contains the base uracil. B. It has a double helix shape. C. It contains 5 phosphate groups per nucleotide. D. It has a backbone of 20 different nucleotides.

Which of the following statements describes a DNA molecule?

B. It has a double helix shape. DNA has a double helix shape. (like a twisted ladder)You probably know the shape, now just learn its name

– Double Helix!!

Specific DNA sequences called “promoters” provide binding sites for the enzyme that synthesizes RNA. Promoters are directly involved in which cellular process?

A. active transport

B. crossing over C. replication D. transcription

Specific DNA sequences called “promoters” provide binding sites for the enzyme that synthesizes RNA. Promoters are directly involved in which cellular process?

D. transcription

Transcription is making (“Synthesizing”) RNA from DNA. It is the only one listed that has both DNA and RNA involved together.

The diagram below shows a pair of DNA nucleotides. The nitrogenous base guanine (G) is labeled.

Which nitrogenous base pairs with guanine?

A. adenine (A) B. cytosine (C) C. thymine (T) D. uracil (U)

The diagram below shows a pair of DNA nucleotides. The nitrogenous base guanine (G) is labeled.

Which nitrogenous base pairs with guanine?

B. cytosine (C) G always pairs with C! (and A with T in DNA).

Memorize these base pairings!!!

Radon is a radioactive gas that is sometimes present in homes. If radon is inhaled, its decay products are deposited in the lungs. Radioactive particles can penetrate cells and cause changes to the cells’ DNA.

These changes in DNA are an example of which of the following?

A. homeostasis

B. mitosis C. mutation D. transcription

Radon is a radioactive gas that is sometimes present in homes. If radon is inhaled, its decay products are deposited in the lungs. Radioactive particles can penetrate cells and cause changes to the cells’ DNA.

These changes in DNA are an example of which of the following?

C. mutation

A mutation is a change to the cell’s DNA

An RNA sequence is shown: AUGCCGAAACGUWhich of the following statements describes how the

RNA sequence specifies the production of an amino acid chain?

A. Each individual RNA base codes for a single amino acid.

B.Each group of three RNA bases codes for a single amino acid.

C.Each group of three RNA bases codes for an enzyme that helps join amino acids together.

D. Each individual RNA base codes for the ribosome location where amino acids are assembled.

An RNA sequence is shown: AUGCCGAAACGUWhich of the following statements describes how the

RNA sequence specifies the production of an amino acid chain?

B.Each group of three RNA bases codes for a single

amino acid. This is not in your packet, but translation, (making

proteins from RNA) groups the RNA based into blocks of 3 (called codons) Ex. “AUG” “CCG” “AAA”

Which of the following describes the function of DNA?

A. encoding genetic information

B. storing energy in chemical bonds C. speeding up biochemical reactions D. destroying substances that enter the cell

Which of the following describes the function of DNA?

A. encoding genetic information

This question was here before as “the function of

Nucleic Acids?”. Did you remember it?

The diagram represents a process that occurs in the nucleus of a eukaryotic cell.

Which of the following statements describes what is happening in this process? A.Molecules of RNA are forming chromosomes.B.A molecule of mRNA is directing

the production of tRNA.C.Molecules of DNA are being packaged for export to

the ribosomes.D.A molecule of DNA is being replicated to make two

identical copies.

The diagram represents a process that occurs in the nucleus of a eukaryotic cell.

Which of the following statements describes what is happening in this process?

D. A molecule of DNA is being replicated to make two identical copies.

Recognize the shape (double helix) of DNA. One piece is becoming two. (replication)

Which of the following processes produces the nucleotide sequence UUA from the sequence AAT?

A. meiosis

B. replication C. respiration D. transcription

Which of the following processes produces the nucleotide sequence UUA from the sequence AAT?

D. transcription

When you see “U”, you know it is RNA! The piece with “T” is DNA! So what process would make RNA from DNA? Transcription

Hemoglobin is a protein that carries oxygen in red blood cells. The hemoglobin molecules produced by some people have one specific amino acid that is different from the amino acid at that position in normal hemoglobin.

Which of the following is the most likely cause of this amino acid variation?

A. The hemoglobin gene contains a mutation.

B. An error occurs during the folding of the hemoglobin protein.

C. Enzymes replace the amino acid once the hemoglobin is produced.

D. An additional amino acid is mistakenly inserted into the hemoglobin during translation.

Hemoglobin is a protein that carries oxygen in red blood cells. The hemoglobin molecules produced by some people have one specific amino acid that is different from the amino acid at that position in normal hemoglobin.

Which of the following is the most likely cause of this amino acid variation?

A. The hemoglobin gene contains a mutation.

Mutations cause variation or things to be different

The diagram below represents the beginning and end products of a process that occurs in the nucleus of a cell.

Which process does the diagram represent? C. transcription 2 strand DNA (with “A, T, C, G”) is making 1 strand

RNA (with “A, U, C, G”). This is transcription

A laboratory technique called polymerase chain reaction (PCR) produces millions of copies of a DNA molecule in only a few hours. PCR is most similar to which of the following cellular processes?

A. mitosis

B. replication C. transcription D. translocation

A laboratory technique called polymerase chain reaction (PCR) produces millions of copies of a DNA molecule in only a few hours. PCR is most similar to which of the following cellular processes?

B. replication Replication copies DNA

Which of the following models most accurately represents the structure of DNA?

A. B.

C. D.

Which of the following models most accurately represents the structure of DNA?

B.

C.

• Look carefully at B and C, Can you see the difference? (also notice GC; AT in both!!!)

In a eukaryotic cell, which of the following processes directly involves DNA?

D. replication of chromosomes

Replication (of DNA) happens with DNA. (the trick to this one is they use “chromosomes” But “chromosomes” are made of DNA. When you see DNA in the question think about what you know it goes with - replication

In a molecule of double-stranded DNA, the amount of adenine present is always equal to the amount of

A. cytosine. B. guanine. C. thymine. D. uracil.

In a molecule of double-stranded DNA, the amount of adenine present is always equal to the amount of

C. thymine. Remember A—T in DNA (and G—C)

Which of the following units are repeatedly joined together to form a strand of DNA?

A. amino acids

B. fatty acids C. nucleotides D. polysaccharides

Which of the following units are repeatedly joined together to form a strand of DNA?

C. nucleotides

Nucleotides are the monomer of nucleic acids (DNA)Remember that from page 2????

During DNA replication, the wrong nucleotide was inserted in the DNA sequence. Which of the following terms describes this situation?

A. mutation B. regeneration C. transcription D. translation

During DNA replication, the wrong nucleotide was inserted in the DNA sequence. Which of the following terms describes this situation?

A. mutation Mutation is a change or some mistake in the DNA

A portion of one strand of a DNA molecule has the sequence shown below.

ACCTGAAGGAssuming there are no mutations in this portion of

the DNA, what is the corresponding sequence on the complementary DNA strand?

A. ACCTGAAGG B. GTTCAGGAA C. TGGACTTCC D. UGGACUUCC

A portion of one strand of a DNA molecule has the sequence shown below.

ACCTGAAGGAssuming there are no mutations in this portion of

the DNA, what is the corresponding sequence on the complementary DNA strand?

C. TGGACTTCC This is comparing DNA to DNA, so we use the rule:

A—T; G—C

The diagram below represents part of a process that occurs in cells.

Which process is represented?

A. meiosis B. osmosis C. replication D. translation

The diagram below represents part of a process that occurs in cells.

Which process is represented?

D. translation

• The letter “U” tell you it is RNA, and amino acids are Being connect (they make Proteins) so Translation

The mold Aspergillus flavus grows on grain. A. flavus produces a toxin that binds to DNA in the bodies of animals that eat the grain.

The binding of the toxin to DNA blocks transcription, so it directly interferes with the ability of an animal cell to do which of the following?

A. transport glucose across the cell membrane into the cytoplasm

B. produce ATP using energy released from glucose and other nutrients

C. transfer proteins from the endoplasmic reticulum to Golgi complexes

D. send protein-building instructions from the nucleus to the cytoplasm and ribosomes

The mold Aspergillus flavus grows on grain. A. flavus produces a toxin that binds to DNA in the bodies of animals that eat the grain.

The binding of the toxin to DNA blocks transcription, so it directly interferes with the ability of an animal cell to do which of the following?

D. send protein-building instructions from the nucleus to the cytoplasm and ribosomes

Transcription build proteins! Tough reading, but look for that clue!!!!