Lab Exam 2 - BIO 105

What are the stages of the cell cycle including the checkpoints?

The cell cycle has four main stages: G1 (first gap), S (synthesis), G2 (second gap), and M (mitosis).

The G1 checkpoint (before S phase), the G2 checkpoint (before M phase), and the M checkpoint (between metaphase and anaphase). 

How long is the average cell cycle?

24hrs

How is mitosis different in plant and animal cells?

Plant cells form a cell plate that becomes a new cell wall, lack centrioles, and divide in meristematic tissues, while animal cells form a cleavage furrow and use centrioles for spindle formation throughout the body. 

What is gene therapy?

Gene therapy is a medical technique that uses genetic material to treat or prevent disease by modifying a person's genes to correct a faulty gene, replace a disease-causing gene with a healthy one, or introduce a new gene to help the body fight disease

What causes genetic diseases?

Genetic diseases are caused by mutations, which can result from inheriting a mutation from one or both parents, or from acquired mutations that occur randomly or due to environmental factors like radiation or chemicals

Besides altering genes, what other approaches have been taken to treat genetic diseases?

What is CRISPR? Why are we so hopeful about CRISPR’s potential?

Where does transcription take place?

In the nucleus in eukaryotes and the cytoplasm in prokaryotes

What molecule is produced by transcription?

Messenger RNA (mRNA)

What is the primary enzyme of transcription?

RNA polymerase

How does mRNA leave the nucleus after replication?

Passing through nuclear pores in the nuclear envelope

What is a codon?

Sequence of three consecutive nucleotides in a DNA or RNA molecule that specifies a particular amino acid or signals the start or stop of protein synthesis

What codon always begins the coding region of a gene?

The AUG codon

Where does translation occur?

In the ribosomes of a cell

What is the significance of the start codon? What is the start codon?

It signals where the ribosome should start building a protein, sets the correct "reading frame" for all subsequent codons, and codes for the amino acid methionine

What is an anticodon?

A three-nucleotide sequence on a transfer RNA (tRNA) molecule that pairs with a complementary three-nucleotide codon on a messenger RNA (mRNA) molecule during protein synthesis

What organelle/enzyme carries out translation?

The ribosome

What two important parts of translation are found at opposite ends of tRNA?

The anticodon loop and the amino acid attachment site

Compare and contrast the structure and function of all three types of RNA.

mRNA is a single-stranded, linear molecule that carries genetic code from DNA to ribosomes

rRNA is a structural and catalytic component of ribosomes

tRNA is a small, folded molecule that delivers specific amino acids to the ribosome

Describe how a ribosome constructs a polypeptide from a piece of mRNA.

A ribosome builds a polypeptide by translating an mRNA sequence into a chain of amino acids through three stages: initiation, elongation, and termination

When does translation stop?

When the ribosome encounters a stop codon (UAA, UAG, or UGA) in the mRNA sequence

You will need to be able to model the process of translation and transcription

ok

What does it mean to say DNA is double stranded?

It consists of two long chains of nucleotides that are twisted around each other, forming a structure called a double helix

What are the backbones of DNA made of?

The backbones of DNA are made of alternating sugar (deoxyribose) and phosphate groups

What type of bonds hold nitrogen base pairs together?

Hydrogen bonds

What type of bonds hold everything else together?

Covalent bonds

What is a nucleotide?

A nucleotide is the basic building block of nucleic acids like DNA and RNA

Be able to label a thorough diagram of DNA’s structure

ok

What is the purpose DNA extraction?

Uses buffers to break membranes to get DNA out of a cell

What is the purpose of extraction buffer?

Keeps pH stable and breaks membranes

What does PCR stand for?

Polymerase Chain Reaction

What is the purpose of PCR?

Duplicate DNA multiple times quickly

A PCR begins by heating DNA to about _____ C in order to _____ the DNA. Next, the temp of DNA is brought to about _____ C allowing _____ to _____. The temp is then brought up to approx _____ C which is the ideal temp for the _____ to _____ the DNA sequence. These three steps are repeated about _____ times until millions of copies of the original DNA are present in the test tube.

95 deg, denature, 64 deg, primers, anneal, 72 deg, enzyme, extend, 32

What is the specific enzyme used in PCR?

TAQ polymerase

What’s special about the enzyme used in PCR compared to the human version?

Can resist higher temperatures

What was the purpose of doing DNA extraction in our lab?

To get DNA out of our cheek cells

What was the purpose of doing PCR in our lab?

To copy our DSI180 Locus

What is CRISPR?

CRISPR can be used to change sequence of DNA. It allows scientists to make targeted changes to an organism's DNA, and is faster and cheaper than the current gene therapy

Clustered Regularly Interspaced Palindromic Repeats

What inheritance patterns does fatal familial insomnia follow?

Autosomal Dominant

fatal familial insomnia is an inherited prion disease that causes progressive loss of sleep, dementia, and motor dysfunction, leading to death

How does gel electrophoresis work?

Electricity is added to samples in an agarose gel to draw charged molecules through the gel

What sugar is the gel made from?

Agarose sugar