Download DNA, Genes and Chromosomes

DNA, Genes and Chromosomes
Vocabulary
DNA, Genes and Chromosomes
Big Ideas
Heredity and Reproduction
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Understand and explain that every organism
requires a set of instructions that specifies its
traits, that this hereditary information (DNA)
contains genes located in the chromosomes of
each cell, and that heredity is the passage of
these instructions from one generation to
another.
DNA, Genes and Chromosomes
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DNA is a large molecule in each cell that
holds its genetic information
This genetic information is used by the cell to
make proteins
It appears in all living organisms
How big is human DNA? Estimates vary from
between 1.5 and 3 m long
Other organisms have DNA with shorter or
longer strands
DNA, Genes and Chromosomes
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Information for all traits of an organism
located in its DNA
DNA found in the nucleus of eukaryotes,
cytoplasm of prokaryotes
DNA, Genes and Chromosomes
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The twisted shape of a DNA molecule is known as a
double-helix of two strands composed of a sugarphosphate backbone connected by nitrogen bases
There are four different nitrogen bases in DNA
– Adenine (A)
– Thymine (T)
– Guanine (G)
– Cytosine (C)
They form base pairs, one on each of the two strands
in the double-helix
– A pairs with T
– C pairs with G
DNA, Genes and Chromosomes
Draw this DNA double-helix into your notebook
DNA, Genes and Chromosomes
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You can refer to a strand of DNA by its sequence of
bases
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A small example: ATGACGTAC
The sequence of bases forms a genetic code
Every three bases code for an amino acid
Amino acids are the building blocks of proteins
A sequence of three letters allows for up to 64 amino
acids
In reality, there are only 20 amino acids
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Some have more than one code
A few codes are used for other things
DNA, Genes and Chromosomes
Chromosomes
 DNA is organized into structures called
chromosomes
 Individual parts of a chromosome are called
genes
 A gene is a section of a DNA molecule that
contains the information to code for one
specific protein
DNA, Genes and Chromosomes
Chromosomes, DNA and genes in a eukaryotic organism
DNA, Genes and Chromosomes
Chromosomes
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Location in the Cell
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Found in the nucleus of eukaryotic organisms
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Found in the cytoplasm of prokaryotic
organisms
Purpose
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To instruct the cell in making proteins
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To transfer genetic information from one
organism to its “children”
DNA, Genes and Chromosomes
Chromosomes
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Role in Heredity
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Carries information about physical
characteristics from parent cells to child cells
DNA, Genes and Chromosomes
Replication
 DNA replication is the process in which a
identical copy of DNA is formed for a new
cell
 Two sides of a DNA molecule unwind and
separate
 New nitrogen bases pair up with the bases
on each half of the DNA forming new copies
DNA, Genes and Chromosomes
Copy this DNA replication example into your notebook
DNA, Genes and Chromosomes
Replication
 Where it occurs
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In the nucleus of eukaryotes
In the cytoplasm of prokaryotes
Purpose
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To prepare copies of DNA for cell reproduction
Consequences of a mistake
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If a mistake is made in copying, a mutation can
occur
Classwork 1- DNA, Genes and Chromosomes
Copy the questions into your notebook (right-side) and answer them
1.
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___ is the molecule that holds genetic information
The structure of the double helix is two _________________ backbones with nitrogen bases
connecting them
The sequence of the four nitrogen bases, a__, t__, g__
and c__, determines what type of _____ _____ will be
made
Amino acids are the building blocks of ______
It takes a sequence of __ DNA nitrogen bases to
determine what amino acid will be made.
Classwork 1- DNA, Genes and Chromosomes
Copy the questions into your notebook (right-side) and answer them
6.
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A ________ is a section of a DNA molecule that
contains the information to code for one specific protein;
a __________ is made up of many of these
DNA __________ is the process in which a identical
copy of DNA is formed for a new cell (mitosis)
Chromosomes are found in the _________ of eukaryotic
organisms and the __________ of prokaryotic
organisms
The length of human DNA is more than 1.5 ___
One strand of DNA has the sequence TGGTCGAAC.
What is the sequence of the opposite strand?