Download An Introduction to DNA and Genetics Directions: As you watch the

Name____________________________________
Date_____________________________________
Section___________________________________
An Introduction to DNA and Genetics
Directions: As you watch the “Tour of Basic Genetics” video segments (from
Learn.Genetics http://learn.genetics.utah.edu/content/basics/ ) fill in the missing
components to complete the notes.
Part 1: What is a trait?
•
List a few examples of traits
•
Some traits are ___________________ and some are controlled by the
________________________.
•
Inherited traits are controlled by ________________. Give an example of
an inherited trait: ________________________________.
•
The ________________________ we speak and the ______________
we like are shaped by the environment which includes our
________________, our ____________________ and our
________________ surroundings. Give an example of how an inherited
trait is influenced by our environment.
STOP!!!! Before you move on to Part 2 of your “genetics tour” complete
the statement below.
•
Instructions providing all the information necessary for a living organism to
grow and live reside in the________________________________ of each
cell. (Hint: in a very important organelle!)
Part 2: What are DNA & Genes? Return to the “Basic Genetics” home page
and and click on “What are DNA & Genes?” to complete the notes below.
• The instructions come in the form of a molecule called_______________.
• DNA is made up of 4 tiny building blocks. Each building block has a
__________________________ and a chemical base that is represented by
the letters _______, ________, _______, and ________.
• DNA molecules have ______ strands that are joined together by
complimentary ______________ pairs.
o _______ pairs with _______
o ________ pairs with _______
• These building blocks function together in larger units called _________.
Each gene is a set of instructions for building a specific ______________.
• A complete set of genes is called a ________________________. A genome
is a set of instructions for building an entire __________________________.
• If every person’s genome has the same genes arranged in the same order.
What makes each person unique?
STOP!!! Before you move onto Part 3 of your “genetics tour” read the
information below this video clip to complete the notes below.
• The human genome has ________ billion letters. Our DNA sequences
contain information for about ______________________ genes. Most of our
________________ code for ____________________, but some code for
_________ molecules.
• All humans have the same ______________ arranged in the same
_____________. What percent of our DNA sequence is the same? _____%
On average, a human gene will have _______ - _______ bases that differ
from person to person. These differences can change the _____________
and ____________________ of a protein, how the protein is made, when it’s
made, or where it is made.
Part 3: What is Inheritance? Return to the “Basic Genetics” home page and
and click on “What is Inheritance?” to complete the notes below.
• When living things reproduce they pass _________ to their ______________.
Through ___________________ reproduction some living things can
reproduce without a partner. Offspring made by asexual reproduction are
____________________ ______________________ to the parent.
• Other living things reproduce with a partner. This is called _______________
reproduction. Offspring made this way inherit ________________ amounts of
___________ from ________ parents.
• Every human being has _________ copies of every _____________. The
copies can be the same or different. The combined output of ALL of our
genes influences our inherited ____________________.
• When a couple has children each parent passes _________ copy of each of
their __________________. For each gene the copies passed from each
parent to their child is different. Which means that each child gets a
_________________ combination of copies of all of their parent’s genes. This
mixing contributes to _____________________ ___________________.
• Because families share genes ____________________ resemble their
____________________ and each other. Unique ___________ combinations
give individual a unique set of inherited _________________________.
• Your DNA holds a ____________________ of our family relationships!
STOP!!! Before you move onto Part 4 of your “genetics tour” read the
information below this video clip to complete the notes below.
•
In your own words explain why is genetic variation important?
•
In asexual reproduction, variation come mainly from _________________.
Mutation introduces permanent changes in a ________ sequence.
•
In sexual reproduction, variation comes from both _______________ and
________________________. Mutation causes different versions
(alleles) of the same ____________. Parent ______________ are
shuffled – or recombined – when sex cells created in the body. Because
of _______________________, sexual reproduction produces more
_______________________ than asexual reproduction.
•
Sex chromosomes determine whether an individual is _________ or
___________________. In most mammals, there is an ______ and
______ sex chromosome. Females have _____ X chromosomes, and
therefore ______ copies of EVERY gene. Males have ___ X chromosome
and ___ Y chromosome. For some genes males inherit just _____ copy.
•
Sex of an organism is NOT always determined by chromosomes. For
example, in some reptiles like turtles ___________________ during egg
incubation will determine the gender of the offspring.
Part 4: What is Mutation? Return to the “Basic Genetics” home page and and
click on “What is Mutation?” to complete the notes below.
•
The differences in our genes come about by a natural process called
________________________. Mutations are extremely common.
•
As a cell copies its DNA before dividing it makes occasional “________.”
Most commonly a single base is __________________ for another.
Sometimes a single base is ___________________ or and extra base is
_________________.
•
Most changes can be repaired by the cell but each time the cell divides
there are a few changes that are NOT repaired. When _______ changes
occur in cells that become __________ or ____________ they can be
passed down to ______________________. Each one of us has about
______ variation that were NOT present in our ______________.
ADDITIONAL NOTES: Thesenotesarenotpartofthe“ToursofBasicGenetics.”Ifyoufinishearly
trytofillinthesenotesonyourown.Or,explorethe“moreabout_____”sectionsofthiswebsite.
• A DNA molecule takes the shape of a twisted ladder. It is what scientists
call a ________________ _________________________.
Draw a strand of DNA and show where a gene would be.
DNA stands for ___________________________________________________.
• Each cell in our body contains a great deal of DNA. If you were to pull the DNA
out of a cell, it would stretch out to be______ meters long.
• In order for all of the DNA to fit into the cell, it is packed into units called
_____________________.
Draw one here.
• Different species cells hold a different number of chromosomes. Each human
cell has_______ chromosomes. The DNA is organized into_______ pairs of
chromosomes. One set came from our________________ and the other set
came from our ________________.
Use the space below to write additional notes about anything else you
found interesting while exploring this website.