Unit 4 ~ DNA Review

DNA: Deoxyribonucleic Acid Unit 4 ~ DNA REview DNA: Deoxyribonucleic Acid Found: in the nucleus of Eukaryote cells RNA: Ribonucleic Acid Made: in the Nucleus and brings message to Ribosomes

Repeating nucleotides Unit 4 ~ DNA REview Shape: Double Helix Repeating nucleotides Nucleotide: 1 Base, 1 Sugar, & 1 Phosphate

1953: Who established the structure of DNA? Unit 4 ~ DNA REview 1953: Who established the structure of DNA? James Watson & Francis Crick Rosalind Franklins work helped ^

Unit 4 ~ DNA REview Gene - a segment of ______ that codes for a protein, which in turn codes for a trait (skin tone, eye color, etc…) Example: TGCCAGTCA

The bases The organic bases are Adenine (A) Thymine (T) Cytosine (C) Guanine (G)

Nucleotides pair in a specific way - called the Base-Pair Rule G C

PO4 sugar-phosphate backbone + bases Joined nucleotides A molecule of DNA is formed by millions of nucleotides joined together in a long chain

Bonding 2 PO4 adenine cytosine PO4 thymine PO4 guanine PO4 PO4

DNA replication is semi- _____________ DNA replication is semi- _____________. That means that when it makes a copy, one half of the old strand is always kept in the new strand. This helps reduce the number of copy error

Unit 4 ~ DNA REview Mutations occur at some time during a person's life and are present only in certain cells, not in every cell in the body. This can occur if a mistake is made as DNA copies itself during cell division. OR can be caused by environmental factors such as ultraviolet radiation from the sun.

RNA DNA remains in the _______________ but in order for it to get its instructions translated into proteins, it must send its message to the ribosomes, where proteins are made. The chemical used to carry this message is Messenger RNA RNA = ribonucleic acid. RNA is similar to DNA except: 1. has one strand instead of two strands. 2. has uracil instead of thymine 3. has ribose instead of deoxyribose mRNA has the job of taking the message from the DNA to the nucleus to the ribosomes.

Translation: Proteins are made from the message on the ______ Unit 4 ~ DNA Review Transcription: The code is read by copying stretches of _____into the related nucleic acid _____ Translation: Proteins are made from the message on the ______

Unit 4 ~ DNA REview

Review Question #1 Which of the following describes the function of DNA? A. storing energy in chemical bonds B. encoding genetic information C. speeding up biochemical reactions D. destroying substances that enter the cell

REVIEW QUESTION #2 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

Review Question #3 During the process of replication, a molecule of DNA unzips, forming two single strands. What makes up each individual strand of DNA? A. paired adenine and uracil bases B. paired thymine and guanine bases C. sugar groups attached to individual amino acids D. bases attached to a sugar-phosphate backbone

Review Question #4 In a sample of double-stranded DNA, 30% of the nitrogenous bases are thymine. What percentage of the nitrogenous bases in the sample are adenine? A. 20% B. 30% C. 60% D. 70%

Review Question #5 Which of the following statements explains why the insertion of a nucleotide in a DNA sequence could result in a physical change in an organism? A. Fatty acids would no longer attach to the DNA strands to transcribe the DNA. B. The DNA would no longer fit through the nuclear membrane to get to ribosomes for translation. C. The sequence of nitrogenous bases in the DNA would no longer code for the correct amino acids. D. Antibodies would no longer recognize the DNA as belonging to the cell and would destroy the DNA.

Review Question #6 AUGCCGAAACGU An RNA sequence is shown below. Which 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.

Review Question #7 During the process of replication, a molecule of DNA unzips, forming two single strands. What makes up each individual strand of DNA? A. paired adenine and uracil bases B. paired thymine and guanine bases C. sugar groups attached to individual amino acids D. bases attached to a sugar-phosphate backbone

Review Question #8 The diagram represents the expression of the genetic code in organisms. Three parts of the diagram are labeled X, Y, and Z. What do X, Y, and Z represent in the diagram? A. X is replication, Y is a gene, and Z is mutation. B. X is crossing over, Y is DNA, and Z is mitosis. C. X is transcription, Y is mRNA, and Z is translation. D. X is meiosis, Y is a chromosome, and Z is transport.

Review Question #9 A DNA sequence is shown below. TAGGAGCAT What is produced when the sequence is transcribed? A. a chain of three amino acids B. a set of three tRNA molecules C. a section of DNA with the base sequence ATCCTCGTA D. a section of mRNA with the base sequence AUCCUCGUA

Review Question #10 The diagram below represents a small section of a DNA molecule. Which section of DNA represents the complementary strand to the section of DNA above? A. A T T C G G G A T A T T B. T T A T A G G G C T T A C. T A A G C C C T A T A A D. A A T A T C C C G A A T

Review Question #11 A sample of human DNA contains approximately 30% adenine and 20% guanine. Based on DNA structure, what are the expected percentages of the other bases in the sample? A. 10% thymine, 40% cytosine B. 20% thymine, 30% cytosine C. 30% thymine, 20% cytosine D. 40% thymine, 10% cytosine

Review Question #12 A mutation occurs in an individual, but the individual’s outward appearance does not change. Which of the following statements describes what most likely occurred to produce this result? A. The mutation deleted a portion of a coding section of the DNA. B. The mutation caused a portion of a coding section of the DNA to repeat. C. The mutation affected a nucleotide in the DNA, but the mutation did not affect the sequence of amino acids synthesized. D. The mutation translocated a group of nucleotides in the DNA, but the mutation did not change the number of base pairs in the DNA.

Review Question #13 A mutation occurs in an individual, but the individual’s outward appearance does not change. Which of the following statements describes what most likely occurred to produce this result? A. The mutation deleted a portion of a coding section of the DNA. B. The mutation caused a portion of a coding section of the DNA to repeat. C. The mutation affected a nucleotide in the DNA, but the mutation did not affect the sequence of amino acids synthesized. D. The mutation translocated a group of nucleotides in the DNA, but the mutation did not change the number of base pairs in the DNA.

Review Question #14 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.

Review question #15 Which of the following features of DNA is most important in determining the traits of an organism? A. the direction of the helical twist B. the number of deoxyribose sugars C. the sequence of nitrogenous bases D. the strength of the hydrogen bonds

Review question #16

The table presents a variety of mRNA three-base sequences (codons) and the amino acids for which these sequences code. Based on the information in the table, which of the following changes is least likely to produce a phenotypic change in an organism? A. GAU to GGU B. GAU to GUU C. GAU to GAC D. GAU to GAA 1st Base of mRNA 2nd base of mRNA 3rd base of mRNA Amino Acid G A Glutamic acid C Aspartic acid U Glycine Valine