Download Unit 2 Lesson 6

Unit 2 Lesson 6 DNA Structure and Function
Cracking the Code
What is DNA?
• The genetic material in cells is contained in a
molecule called deoxyribonucleic acid, or _____.
• Scientists describe DNA as containing a code. A
code is a set of rules and symbols used to carry
_____________________.
• To understand how DNA functions, you first need
to learn about the structure of the DNA molecule.
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Unit 2 Lesson 6 DNA Structure and Function
Unraveling DNA
What does DNA look like?
• Experiments and imaging techniques have helped
scientists to infer the shape of DNA.
• The structure of DNA is a _________________
shape called a double helix.
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Unit 2 Lesson 6 DNA Structure and Function
What does DNA look like?
• The two sides of the ladder are made of
__________ and _____________ groups.
• The rungs of the ladder are made of pairs of
_________.
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Unit 2 Lesson 6 DNA Structure and Function
What does DNA look like?
• A base, a sugar, and a phosphate group make a
building block of DNA called a ________________.
• There are four different nucleotides in DNA.
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Unit 2 Lesson 6 DNA Structure and Function
What does DNA look like?
• The bases in nucleotides are paired, or _________.
• A__________ always pairs with t_________ (A-T).
• C__________ always pairs with g__________ (C-G).
• The __________ of the nucleotides in DNA is a code
that carries information.
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Unit 2 Lesson 6 DNA Structure and Function
What does DNA look like?
• ____________ are segments of DNA that relate
to a certain trait.
• The code in the nucleotide order has information
about which ___________ the cells should build.
• The types of proteins that your body makes help
determine your ____________.
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Unit 2 Lesson 6 DNA Structure and Function
Replication and Mutation
How are copies of DNA made?
• The cell makes copies of DNA molecules through a
process known as __________________.
• During replication, the two strands of DNA
separate.
• The bases on each side of the molecule are used
as a pattern for a new strand.
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Unit 2 Lesson 6 DNA Structure and Function
How are copies of DNA made?
• DNA unzips with the help of proteins. It unzips in
the middle where the bases meet.
_____________ nucleotides are added.
• When replication is complete, there are two
identical DNA molecules.
• Before a cell _______________, it copies its DNA.
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Unit 2 Lesson 6 DNA Structure and Function
What are mutations?
• ___________________ are changes in the
number, type, or order of bases on a piece of DNA.
• There are three main kinds of mutations: deletions,
insertions, and substitutions.
• In a ________________ mutation, a base is left out.
• In an ______________ mutation, an extra base is
added.
• In a ________________, one base replaces another.
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Unit 2 Lesson 6 DNA Structure and Function
What are mutations?
• Which type of mutation is shown in each row?
(The first row is the original sequence.)
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Unit 2 Lesson 6 DNA Structure and Function
Protein Factory
• Some of the information in the DNA is copied to a
separate molecule called _______ or ribonucleic acid.
• RNA is used to build proteins.
• Like DNA, RNA has a sugar-phosphate backbone and
the bases adenine (A), guanine (G), and cytosine (C).
• Instead of thymine (T), RNA contains uracil (U).
• Three types of RNA have special roles in making
proteins.
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Unit 2 Lesson 6 DNA Structure and Function
What is the role of DNA and RNA in
building proteins?
• When a cell needs to make a protein, it makes an
RNA copy of a section of the DNA. This is called
_______________.
• DNA is used to make a complementary strand of
messenger RNA (mRNA).
• The information in the mRNA is then used to build
proteins. This is called _______________.
• The mRNA goes through a ribosome and tRNA
brings amino acids to make a protein.
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