Mod A Unit 2, Les 6 DNA Structure And Function Flashcards
What is DNA?
The genetic material of a cell that contains information needed for the cell’s growth and other activities. It also determines the inherited characteristics of an organism
Which material does most of the work of a cell and also makes up most of the cell’s structure?
Protein
What is meant by the DNA’s code?
This is a set of rules and symbols used to carry information
The structure of DNA is described as a twisted ladder shape. What is the term used to describe this?
Double helix
- The two sides fo the DNA ladder often called the “backbone” is made by alternating two materials called…? (See p. 150 for more details)
- The rungs in the ladder are made by materials called ….?
- Sugars and phosphates
2. Pairs of bases
A base, a sugar, and a phosphate group make a building block of DNA known as a ….? these repeating chemical units join together to form the DNA molecule.
A nucleotide
These 4 bases are called: (remember “All Tigers Can Growl”)
Adenine, Thymine
Cytosine, Guanine
The bases pair together in a special, complimentary way. (They fit together just right) Which two pairs always go together?
Adenine with Thymine
Cytosine with Guinine
What are the segments of DNA that each relate to a certain trait?
Genes
The process by which a cell is able to make copies of DNA molecules is called…?
Replication
What happens during replication? Remember, this happens before a cell divides.
- The 2 strands of DNA separate (like being unwound)
- The bases on each side of the molecule are used as a pattern for a new strand to be made. 3. Adenine attach to thymine etc.new strands are made with 1 old DNA strand and 1 new one. (See p. 152 for a diagram)
What are mutations?
Changes in the number, type, or order of bases on a piece of DNA
What are the 3 types of mutations? Explain each
- Deletion: a base is left out
- Insertion: a extra base is added
- Substitution: one base replaces another (most common type) Note: mutations can be beneficial, neutral, or harmful)
How do mutations happen?
Usually, there are random errors. Another possibility is when DNA is damaged by chemical agents called mutagens (examples are ultraviolet light or chemicals in cigarettes.
What is a genetic disorder?
This is a disorder that results fro mutations that harm the normal function of a cell. (Such as sickle cell anemia). They are inherited (passed down from parents)
How does the cell use DNA to make proteins?
- Some Info from DNA is copied to ribonucleic acid (RNA).
- The copy is used to build proteins. Not all instructions are needed all the time. Some DNA is protected inside the cell’s nucleus
RNA contains a sugar-phosphate backbone and 4 bases. What are these bases called?
Adenine (A), guanine (G), cytosine (C),and uracil (U). (First 3 are just like the bases in DNA)
There are 3 types of RNA. Each type has a special role in making proteins. What are they called?
- Messenger RNA,
- Ribosomal RNA
- Transfer RNA
What is transcription?
This is when a cell needs a set of instructions for making a protein and it makes an RNA copy of the needed section of DNA. DNA and messenger RNA are needed (mRNA).
Explain the process of transcription.
To help you remember, imagine taking a book off of the bookshelf and only copying the pages you need to do your work!
*only specific genes needed are copied from the DNA. 1. DNA is used as a template to make a complementary strand of mRNA. 2. DNA opens up where the gene is located. 3. RNA bases match up to the bases on the DNA template. When done, the mRNA is released and the DNA molecule closes.
What is translation?
The process of making proteins from RNA
What is a ribosome?
An organelle made of ribosomal RNA (rRNA)
What happens during translation?
- The mRNA passes through the ribosome.
- Transfer RNA (tRNA) molecules deliver amino acids to the ribosome
- Each group of 3 passes on mRNA codes for 1 amino acid and they join together to make a protein. (See p. 155)
What is Erwin Chargaff known for?
He found that:
Amount of Adenine = amount of thymine
Amount of guanine = amount of cytosine
What are Rosalind Franklin and Maurice Wilkins known for?
Took x-ray images of DNA molecule
What are James Watson and Francis Crick known for?
Proposed a double-helix model of DNA
