Name: ____________________
What do Genes Look Like? - notes (part 1)
Genes:
What are they?
Where are
they?
I. ___________________________ - segments of DNA that carry hereditary
instructions and are passed from parent to offspring; genes are located on
______________________________
Chromosome
DNA
The structure of
DNA
II. ___________________________ – Hereditary material that controls all the activities
of a cell and provides the instructions for making proteins (proteins are the building
blocks of the body and determine a person’s traits)
A. DNA is made of _________________________________
B. Nucleotides have _________________ parts; 5-carbon
__________________, phosphate group, nitrogen base
1. Nucleotides are identical except for the nitrogen base
2. A nucleotide can contain 1 of 4 Nitrogenous Bases• ____________________________________
• ____________________________________
• ____________________________________
• ____________________________________
Nitrogen
bases can
be
Adenine
Guanine
Cytosine
Thymine
The amount of Adenine = Thymine, Cytosine = Guanine (Chargaff’s Rule)
Replication –
how DNA
makes a copy of
itself
III.
Name: ____________________
The Double Helix- 1953, 2 American scientists, ______________________
and Crick, discovered the structure of DNA using the X-rays made by
Rosalind Franklin
A. 2 __________________wound around each other like a twisted ladder
B. Strands are held together by _________________________ between
nitrogenous bases.
C. Adenine bonds to _____________________ and Cytosine bonds to
__________________
Structure of DNA
_________
bonds
Sugar Phosphate
Backbone
Adenine
Thymine
Cytosine
Guanine
IV.
_________________________________: Before a cell divides to produce
new cells, DNA on every chromosome is copied so that each new cell has an
identical set of chromosomes.
Simulate Replication: Make a complimentary strand of DNA
ATT CGT ACG TTT ACT
___ ___ ___ ___ ___
Self Check –
part 1
1.The process of Making a copy of DNA during mitosis is called ________________
2. How do bases pair up during replication?
3. Replicate the following strand of DNA :
ACA
GGC
TAT
AAT
______ ______ ______ ______
__
__
__
__
4. Where is DNA stored in a eukaryotic cell? ______________________________
Name: ____________________
What do Genes Look Like? - notes (part 2)
From DNA to
Protein
I. How DNA works – DNA cannot leave the nucleus. A copy of the DNA code is made
in the nucleus into RNA. RNA travels out of the nucleus to the ribosome where the code
is read and the protein is assembled.
A. The nitrogen bases in every gene make a _______________________
B. Every three bases makes one ________________________
C. One codon is the code for one ________________________ _________________
D. Long chains of amino acids make___________________________.
E. Proteins determine an organisms characteristics and traits
Translation:
Using RNA and
The Genetic
Code to make
Proteins
II. Making a Protein: Translation
DNA in the Nucleus:
ATA GCT CCG TTA
Code is made into RNA: UAU CGA GGC AAU
***In RNA Thymine is replaced by _________________******
Amino Acid Chain is made at the ribosome: Tyrosine: Arginine: Glycine: _______________
Genetic
Mutations
III.
__________________________- changes in the DNA sequence that affect
genetic information; Can affect all types of cells (not all are harmful).
A. ______________________- affect sex cells – inherited by offspring (ex- Down
Syndrome)
B. ____________________________– affect other cells- not inherited by offspring
(many cancers caused by somatic mutations)
Two Types of
DNA mutations
IV. 2 types of mutations
A. _____________________________ (#1) - changes in a single gene. 2 types of
gene mutations1. _______________________________- affect only one nucleotide
*Can be caused by substitutions
2. _____________________________- type of point mutation where
nucleotide is inserted or deleted; affects every amino acid after that point.
*Can be cause by insertions or deletions
B. __________________________________(#2) - changes in whole chromosomes.
4 types of chromosomal mutations.
1. _______________________-- loss of all or part of chromosome
2. _______________________- segment of a chromosome is repeated
3. _______________________ -chromosome becomes reversed
4. ______________________- part of a chromosome breaks off and attaches to a
different chromosome
Name: ____________________
Effects of DNA
mutations
V. What are the effects of________________________-?
A. _______________________ are altered.
B. __________________are unable to perform “normal” functions.
Sometimes _____________________are harmful, sometimes there is no affect, and
sometimes mutations can be helpful. (Helpful when mutation produces a trait that
aids in survival)
Changing DNA
on purpose
VI. ___________________________- when humans change the genes of an organism
to achieve a desired result
A. ____________________________- allowing only the individuals with desired
traits to reproduce. 2 types
1. _________________________-crossbreeding dissimilar individuals:
offspring will have the best of both
 Ex: donkey x horse = mule
2. __________________________-breeding individuals with similar
characteristics: maintain certain characteristics in offspring
 Ex: German Shepard x German Shepard = German Shepard
VII. _______________________________ – Desired genes are removed from one
organism and added or recombined into another organism. This forms a transgenic
organism with recombinant DNA
A. This is used to make proteins not normally made by the cell. Can be used to
produce: Drugs like insulin, Vaccines, Plants resistant to Insects, Reduce
pollution, Better crops/meat
DNA and
Evolution
VIII. Evolution –natural process through which species ____________________over
time
A. The __________________________“selects” the best traits – only those
best suited will survive and pass on their traits to offspring.
B. ___________________________– occurs because of genetic differences
caused by mutations in DNA