Grade 9 Science Related Reading/Biology
Grade 9 Biology
9L.5: INHERITANCE
What Does DNA Look Like?
Task 1 - Pre- Reading Activity
List some information that you may know about the DNA
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Grade 9 Science Related Reading/Biology
Task 2 – Reading Activity
What Is DNA?
Inherited traits are traits that are passed
from generation to generation. To understand how inherited
traits are passed on, you must understand the structure of
DNA. DNA (deoxyribonucleic acid) is the molecule that
carries the instructions for inherited traits. In cells, DNA is
wrapped around proteins to form chromosomes. Stretches
of DNA that carry the information for inherited traits are
called genes. A strand of DNA looks like a twisted ladder.
This spiral shape is called a double helix.
What Is DNA Made Of?
DNA is made up of smaller units called nucleotides. A
nucleotide is made of three parts: a sugar, a phosphate,
and a base. The sugar and the phosphate are the same for
each nucleotide. However, different nucleotides may have
different bases.
There are four different bases found in DNA nucleotides.
They are adenine, thymine, guanine, and cytosine. Scientists
often refer to a base by its first letter: A for adenine, T for
thymine, G for guanine, and C for cytosine. Each base has a
different shape.
Before a cell divides, it makes a copy of its genetic information
for the new cell. The pairing of bases allows the cell to replicate,
or make copies of, DNA.
Identify What are two
things that are the same in
all nucleotides
_______________________
_______________________
_______________________
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Grade 9 Science Related Reading/Biology
DNA database unlocks map to genetic disease
(ABC Science) Thursday, 6 September 2012
A massive DNA database has generated a map of the genetic switches that impact
everything from hair loss to cancer, and opened the door to revolutionary treatments
for a host of diseases, say researchers."This is a major step toward understanding the
wiring diagram of a human being," says researcher Michael Snyder of Stanford
University.
The Encyclopedia of DNA Elements (ENCODE) enables scientists to assign specific
biological functions for 80 per cent of the human genome and helps explain how genetic
variants affect a person's susceptibility to disease. It also exposes previously hidden
connections between seemingly unrelated diseases such as asthma, lupus and multiple
sclerosis, which are linked to specific genetic regulatory codes for proteins that regulate
the immune system.
A key insight revealed in a host of papers published in the journals Nature, Science and
Cell is that many diseases result from changes in when, where and how a gene switches
on or off rather than a change to the gene itself. Genes occupy only a tiny fraction of the
genome, and most efforts to map the genetic causes of disease were frustrated by
signals that pointed away from genes. Now we know that these efforts were not in vain,
and that the signals were in fact pointing to the genome's operating system.
Another significant finding is that this blueprint of genetic switches can be used to
pinpoint cell types that play a role in specific diseases without needing to understand
how the disease actually works. This in-depth map of the human genetic code has also
altered scientific understanding of how DNA works. Ian Dunham of the European
Bioinformatics Institute says, “ENCODE gives us a set of very valuable leads to follow to
discover key mechanisms at play in health and disease, those can be exploited to create
entirely new medicines, or to repurpose existing treatments”
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Grade 9 Science Related Reading/Biology
Task 3 – Post Reading Activity
Q1: Where are genes located? What do they do?
________________________________________________________________________________
________________________________________________________________________________
Q2: How are the four kinds of DNA nucleotides different from each other?
________________________________________________________________________________
________________________________________________________________________________
Q3: How is DNA related to chromosomes?
________________________________________________________________________________
________________________________________________________________________________
Q4: The diagram shows part of a strand of DNA. Using the order of bases given in the top of the
strand, write the letters of the bases that belong on the bottom strand.
Q5: Choose the best answer
1.What are chromosomes made of?
a. inherited characteristics
b. generations
c. cells and structures
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
3. The subunits that make up DNA are called
a. phosphates.
c. amino acids.
b. nucleotides.
d. bases.
4. To be copied, a DNA molecule splits
a. across the top.
b. down the middle.
c. along the sides.
d. along the phosphates.
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Grade 9 Science Related Reading/Biology
Q6:Read the words in the box. Read the sentences. Fill in each blank with the word or phrase
that best completes the sentence.
cytosine
double helix
bases
thymine
1.The twisted ladder shape of DNA is called a ______________________.
2.The rungs of the ladder are made of a pair of ______________________.
3.Guanine pairs with ______________________.
4.Adenine pairs with ______________________.
Q7: Choose any word from the text and fill this map
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