Directed Reading Chapter 6
Name______Class______Date______
Directed Reading Chapter 6
Section: What Does DNA Look Like?
_____1.What are chromosomes made of?
a.inherited characteristics c. cells and structures
b.generations d. protein and DNA
_____2.What is the name of the material that determines inherited characteristics?
a.deoxyribonucleic acid c. RNA
b.ribosome d. amino acid
The Pieces of the puzzle
3.The subunits that make up DNA are called
a.phosphates. c. amino acids.
b.nucleotides. d. bases.
4.What two things must DNA be able to do?
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5.Why must DNA be able to be copied?
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6.Scientists were surprised about how much the DNA molecule could do, because they thought only ______molecules could give instructions and be copied during cell division.
7.What three things is a nucleotide made of?
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8.What are the four bases of a nucleotide?
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9.What four letters stand for the four types of bases?
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10. According to Chargaff’s rules, the amount of ______always equals the amount of thymine.
11.According to Chargaff’s rules, the amount of guanine always equals the amount of ______.
12. Rosalind Franklin used a process known as ______to make images of DNA molecules.
13.What shape did Franklin’s images show?
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14.What did James Watson and Francis Crick’s model of DNA look like?
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15.What two things did this model eventually help explain?
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DNA’s double structure
16. The twisted ladder shape of DNA is called a(n) ______
17.What molecules form the sides of the ladder?
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18.What are the rungs of the DNA ladder made of?
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Directed Reading A continued
Match the correct description with the correct term. Write the letter in the space provided.
_____ 19. pairs with adenine
_____ 20. pairs with guanine
21.How did the double helix structure match Chargaff’s observations?
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Making copies of DNA
22. The pairing of bases allows the cell to ______, or make copies of DNA.
23. Both sides of a DNA molecule are ______, binding only with their match.
24.Where is a molecule split during replication?
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25.After a DNA molecule splits, what is added to each side of the ladder?
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26.How often is DNA copied?
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27.What in the cell helps with unwinding, copying, and rewinding the DNA?
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Section: How DNA Works
1.How much DNA does a single cell in your body hold?
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Unraveling DNA
_____2.What shape does DNA take in a cell that lacks a nucleus?
a.a loose loop c. a tight chain
b.a structure d. a protein
_____3.What are the structures that strands of DNA are bundled into in a cell with a nucleus called?
a.nucleotides c. chromosomes
b.loose loops d. tight chains
4.A string of nucleotides that give the cell information about a certain trait is known as a(n) ______.
5.How many chromosomes does a human cell have before division?
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6.When a cell is ready to divide, how many chromatids make up a chromosome?
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Genes and Proteins
7.The ______code is read like a book.
8.The alphabet of the code is made of the ______.
9.Groups of three bases are the codes for specific ______.
10.__A long string of amino acids forms a(n) ______.
11. Instructions for making a protein are given by each ______.
12.List two examples of things proteins help determine about you.
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13. Several forms of RNA or ______help change DNA code into proteins.
14. Because it is so similar to ______, RNA can serve as a temporary copy of a DNA sequence.
15. The “factory” that assembles proteins is known as a(n) ______.
16. A mirror-like copy of DNA called ______moves from the nucleus to the ribosome.
17. Another form of RNA called ______matches amino acids with the bases on the messenger RNA.
Put the following steps in making a protein in order by putting a number in the space provided: 1 for step 1, 2 for step 2, etc.
_____ 18. The RNA copy is fed through the ribosome.
_____ 19. Transfer RNA molecules deliver amino acids to the ribosome.
_____ 20. Transfer RNA molecules pick up amino acids from the cytoplasm.
_____ 21. The amino acids are joined to make a protein.
_____ 22. A mirrorlike copy of the gene is made of RNA.
changes in genes
23. Changes in the number, type, or order of bases on a piece of DNA are known as ______.
Match the correct definition with the correct term. Write the letter in the space provided.
_____ 24. A base pair is added.
_____ 25. A base pair is replaced.
_____ 26. A base pair is removed.
27.Physical or chemical agents known as ______can cause mutations in DNA.
28.List two examples of mutagens.
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An example of a substitution
_____ 29. Sickle cell disease is caused by a(n)
a.substitution mutation. c. insertion mutation.
b.deletion mutation. d. blood vessel mutation.
Uses of genetic knowledge
_____ 30. The manipulation of individual genes within organisms by scientists is called
a.mutation. c. genetic property.
b.drug enhancement. d. genetic engineering.
31.List two possible uses of genetic engineering.
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32. Because DNA is unique, DNA ______can identify the unique patterns in an individual’s DNA and help solve crimes.
33._Only identical twins have truly identical ______.
34. A scientifically created organism that has an exact copy of another organism’s genes is a(n) ______.
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