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Warm-Up Answer these questions on scratch paper

By Joan Roberts,2014-06-19 19:19
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Warm-Up Answer these questions on scratch paper

    Unit 4 DNA

    Outline 4E

    OUTLINE OBJECTIVE: DNA Replication

    Warm-Up: Answer these questions in your notes: 1. What is the function of DNA?

    2. What are the 3 parts of a DNA nucleotide? 3. How do we describe the shape of a DNA molecule? 4. Why is DNA replication necessary before cell division occurs?

    Chromosome Structure

     1) _ _ _ is extremely long the

    2) _ _ _ _ _ _ _ _ _ in the nucleus

    of a human cell contains over 1

    meter of DNA!

     DNA wraps tightly around

    histones (protein), forming

    structures called 3)

    _ _ _ _ _ _ _ _ _ _ _.

     Nucleosomes pack together

    tightly, coiling and folding to form

    4) _ _ _ _ _ _ _ _ _ _ _. (Does it

    always stay that way?)

    Word Bank: Covalent, DNA, strands, nucleus, template, chromosomes, chromatin,

    nucleosomes, base pairing, strand, nucleotides, complementary, weak, replication, enzymes, hydrogen bonds

DNA Replication

     Because of the rules of 5) _ _ _ _ - _ _ _ _ _ _ _ (A-T share 2

    hydrogen bonds, C-G share 3 H-bonds),

    ; Each 6) _ _ _ _ _ _ has all the information needed to reconstruct

    the other half they are said to be 7) _ _ _ _ _ _ _ _ _ _ _ _ _.

    ; Each strand serves as a 8) _ _ _ _ _ _ _ _ by which a new

    strand can be made.

     Before a cell can divide, it must duplicate its chromosomes DNA

    9) _ _ _ _ _ _ _ _ _ _ _. (pg. 297 in your Text)

    4e PAGE 2 The process is carried out by 10) _ _ _ _ _ _ _:

    1. Helicase

    ; Unzips” the DNA molecule by breaking the weak

    11) _ _ _ _ _ _ _ _ _ _ _ _ _.

    ; The point of separation is called the replication fork (there can

    be many forks at once).

    2. DNA polymerase (III)

    ; Binds to each of the separated 12) _ _ _ _ _ _ _ of DNA.

    ; They move along the original DNA strands IN OPPOSITE

    DIRECTIONS, assembling 2 new chains from 13) _ _ _ _ _ _ _

    _ _ _ _ found in the 14) _ _ _ _ _ _ _ using each original

    strand as a template.

    ; Nucleotides are joined to the chain by 15) _ _ _ _ _ _ _ _ bonds

    between phosphates and sugars and the complementary

    strands are held together by 16) _ _ _ _ hydrogen bonds.

Word Bank:

    Covalent, DNA,

    strands, nucleus,

    template,

    chromosomes,

    chromatin,

    nucleosomes, base

    pairing, strand,

    nucleotides,

    complementary, weak,

    replication, enzymes,

    hydrogen bonds

    ; Complete a

    complementary

    DNA strand for this nucleotide sequence:

    T-A-C-T-T-C-T-A-A-T-G-T-G-A-A-G-C-A

    (There are over 30,000,000 base-pairs in the smallest human

    chromosome)

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