Biology Quiz 1 Flashcards
To become fluent in these topics. Give 2 examples for each.
What does DNA’s structure explain?
The stability of life, how genetic info is stored, how genetic info is passed on, and the mutability of life.
What is Photo 51 taken by Rosalind Franklin?
It was the first picture of DNA, taken in 1951. It showed that DNA was a doubel helix that was 4 units wide.
Where is genetic information stored?
In the sequence of the bases.
What are the bases of DNA?
Adenine, cytosine, guanine, and thymine
What are the base pairing rules of DNA?
AT, GC
What is a DNA nucleotide?
It’s the molecule that makes up DNA.
It consists of a phosphate group, deoxyribose (a type of sugar), and a nitrogenous base.
What is a DNA backbone?
It’s a strand of DNA made by the connection of phospate in different nucleotides.
What bond is used to join DNA bases?
A hydrogen bond
What are the differences between DNA and RNA?
DNA (deoxyribonucleic acid) and RNA (ribonucleic acid) are different because:
- DNA is made of deoxyribose, while RNA is made of ribose
- Instead of having the base thymine, RNA has the base uracil
- RNA is single stranded, unlink DNA
What is protein?
Proteins are complex molecules made of amino acids that perform specific functions.
Explain how DNA is converted into protein.
- DNA makes a copy of itself called “coding DNA”
- The coding DNA is then copied to mRNA in a process called TRANSCRIPTION
- The mRNA leaves the cell’s nucleus to go to the ribosome
- The mRNA is read by tRNA in sections of 3 called “codons”
- The mRNA is converted to amino acids by tRNA in a process called TRANSLATION
- All the amino acids eventually join together in a link called a polypeptide chain, which eventually becomes a protein
What are the 3 types of RNA?
mRNA (messenger RNA, takes genetic information from the nucleus to the ribosome)
tRNA (converts mRNA into protein)
rRNA (is what makes up a ribosome)
What is a ribosome?
It’s the cell’s organelle that converts mRNA into protein.
Where is DNA found in a cell?
The nucleus
What is DNA replication?
It’s when DNA makes a copy of itself.
What are the molecules involved in DNA replication?
Helicase: splits the double helix in half
Primase: coats the existing DNA strands, telling the POLYMERASE where to build
Polymerase: builds new DNA
Ligase: closes the gaps between Okazaki fragments on the lagging strand
What is the difference between leading and lagging strands in DNA replication?
Leading strand: since polymerase can only build in a set direction, the LEADING strand simultaneously builds in the same direction that the helicase is unzipping the DNA in
Lagging strand: since polymerase builds in the opposite direction, it can only build in short bursts called “Okazaki fragments”. This leaves short, empty spaces where the polymerase didn’t build. The ligase “glues together” these empty spaces.
What does semi-conservative mean?
In DNA replication, it means that each new strand is made up of one original strand and one new strand.
How do you use a microscope?
- Position and fasten the slide under the microscope
- Start on low power
- Use the coarse adjustment knob (big knob) to change the elevation of the stage
- Repeat these steps when you transition from low to medium to high power
- when you’re in high power, use the fine adjustment knob (little knob)
What was the role of everything in the DNA extraction lab?
Detergent: breaks the cell membrane and nucleus to get the DNA out
Enzyme (meat tenderizer): unwinds the proteins that DNA is built around
Alcohol: decreases the solubility of the dissolved DNA, makes it form into clumps
