1. The role of DNA in heredity
A DNA molecule looks like a twisted ladder.
Its shape is called a _____________ ______________.

2. The two sides of the DNA ladder are made of sugar molecules alternating with ____________ molecules.
The rungs of the DNA molecule are made of chemical building blocks called __________.
The four bases found in ______ are adenine (A), thymine (T), cytosine (C), and guanine (G).

3. DNA replication is the process of a DNA molecule making a ________ of itself.

4. DNA replication ensures that each _______________ _________has an exact copy of the DNA from the parent cell.

5. DNA replication
Replication begins with the partial unwinding of the ___________________ ________________.
The base _____________ separate.
A special molecule moves along each original strand of DNA and “reads” the bases.
A new strand is assembled along each original strand. (New pieces come from the __________.)
The strands re-twist and two ________________ molecules are produced.

7. Protein synthesis
In total, the DNA in one of your cells contains about 3 ________________ base pairs!
The order of base pairs along a gene is called its _______ _______.
What is the base sequence of this gene segment?

8. Protein synthesis _____________ control the production of proteins.
For example, the color of your eyes is determined by a ________________.
The production of proteins in the ___________ is called protein synthesis.

10. Protein synthesis
The order of base pairs along a gene forms a _________ that tells a cell which protein to make.
Sets of three bases along a strand of DNA form three-letter codes that tell the cell which ___________ __________ make up the protein.
There are 20 different amino acids, so these amino acids can be put together in many ways to make __________________ of different proteins!

12. Protein synthesis
Messenger RNA copies the gene and carries it out of the ___________________.
Transfer RNA from the cytoplasm ___________________ the three letters.
Transfer RNA matches the right ___________ __________ to messenger RNA sequence.
The amino acids are linked together on the ribosome to form a _____________ strand.

13. 12.1 Mutations
A ______________ is a change in the hereditary material of an organism
Mutations can happen in any _____ & in any gene.

15. 12.1 Genetic disorders
A genetic disorder is an abnormal condition that an organism ________ from its __________.
One chromosome pair has a mutated extra chromosome.
Can you find it?

16. 12.1 Mutations
Doctors use a procedure called ________________ to find out if a baby could have Down’s syndrome.
The doctor removes a small amount of the fluid that surrounds the developing baby and examines the _____________________.