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CHAPTER 8 – HOW GENES WORK (DNA)

 

UNDERSTANDING DNA

There were ___ major groups of scientists that researched DNA (whether they were trying to or not!)

 

_____________________________ discovered that genetic material, or DNA, could be transferred between living & dead bacteria.

 

He was trying to identify two strains of Pneumococcus bacteria, when he observed  _______________________, a process in which a bacterium takes up foreign DNA.

 

One strain of Pneumococcus formed ___________________ colonies, and one strain formed __________________ colonies. To determine which bacteria were virulent, he injected BOTH strain into mice. This is what happened… (Figure 8-1) GRIFFITH’S EXPERIMENT:

 

 

 

 

 

Griffith found that:

 

 

____________________ identifies the agent of transformation.

 

Was the substance that made nonvirulent bacteria -> virulent bacteria _________________ or _____________?

 

Experiment 1

 

Experiment 2

 

His research proved that __________________________________________________ in these bacteria

 

Each organism has a _____________________ combination of characteristics encoded in _________________________________________

___________________________ & _________________________ confirmed that DNA is the genetic material.

 

They performed an experiment using _________________________________ sulfur (______) & phosphorus (______), & viruses that infect bacteria.

 

This is what happened: (Figure 8-2)

 

 

 

 

 

What did they conclude?

 

How Scientists Determined the Structure of DNA

 Scientists KNEW that DNA: 

* ____________________________ (Deoxyribose)

* ____________________________

* ____________________________ (TWO groups)

                        __________________ - larger, two-ringed bases (ADENINE, GUANINE)

                                                __________________ - smaller, single ringed bases (CYTOSINE, THYMINE)

 

 

 

 

 

_____________________________ developed ______________________________.

 

A = T, C = G

(The amount of Adenine = the amount of Thymine in a DNA molecule, and the amount of Cytosine = the amount of Guanine)

  

 

_____________________________ used X-Ray diffraction images to suggest that DNA resembles a tightly coiled spring, a shape called a ________________.

 

 

___________________________ & __________________________ (1950’s) built a model proving the structure of DNA is a _______________________  _____________________, composed of two strands of nucleotides held together by hydrogen bonds. They won the ____________________________ in 1962.

 

  

 

REPLICATION - HOW DNA IS  COPIED

 

_____________________________ - The process of copying DNA. This must occur ____________________  ____________________________________________

 

The 2 strands of the double helix are _____________________ to one another, which means that the ____________________ of _____________ on one strand determines the sequence of bases on the other strand.

 

When the strands are separated, a _____________________________________ is made from the original.

 

 

 

 

 

 

 

 

The process of ____________________ involves several __________________-

 

During ________________________, a ________________________ strand of DNA is made for each original strand of DNA. For EXAMPLE, if a portion of the original, or “______________” strand is CCTAGCT, the new strand will be GGATCGA.

 

What will be the complementary strand of DNA if the original strand reads TAGCCATTG  ?

                                                                                                                         _____________

A ____________________ is a change in DNA. This can occur if a base is accidentally inserted, left out, or substituted for another base during replication. This can result in ____________________  __________________, which can turn out to be lethal. For example, ________________________________ is a  single gene disorder in which ___________________ is substituted for another. An entirely different ___________________ is produced, resulting in sickled (misshapen) Red Blood Cells, anemia, heart disease & kidney disease.

 

A ____________________ is an environmental agent such as ultraviolet light & chemicals that can cause defects in DNA structure, or ___________________.

 

 

 

HOW PROTEINS ARE MADE

 

________________________________ - The use of the genetic information in DNA to make proteins.

 

2 Stages of Gene Expression: 

 

DNA   -> (transcription) ->   RNA    -> (translation) ->   PROTEIN

 

HOW DNA MAKES RNA (TRANSCRIPTION)-

 

 

 

 

THREE TYPES OF RNA:

 

 

  

_____________________________ - Genetic information encoded in _________ is transferred to an ________ molecule

 

 

The Genetic Code

 

Every ______ nucleotides in ______ specifies a particular _________________________

Each of these ________________________   ____________________ is called a ________________.

The ____________________ of amino acids in a __________________ determines:

 

 

(REFER TO GENETIC CODE TABLE FROM BOOK)

 

 

 

 

 

__________________________________ - Correspondence sequence between nucletide triplets in _________ and amino acids in ___________________

Any of the ______ bases (A, U, C, G) found in ___________ can occur at any of the _____ positions of a ______________.

Thus, ______ different possible ________________________ are possible in the genetic code. (4X4X4 = 64)

 

Since there are ______ possible _____________, but only ______ different ___________________________, more than ____ codon may specify a single _______________________

 

START Codon __________ initiates the start of protein production.

 

STOP Codons _________, __________, & ___________ specify the _______ of an __________________ sequence, or ____________________.

 

The code contained in a particular gene results in a ___________________  ____________________.

 

 

HOW RNA MAKES PROTEINS - TRANSLATION

 

_____________________________ - The process by which a genetic message is deciphered.

 

 

What happens?

    

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