Lecture 15 - How do genes make cell? Flashcards
Different cells in body are
Brain cells Heart muscle cells RBC Fat cells Nerve cells
A cell must
Respond to environment
Make and break molecules
Generate energy
Maintain itself
Typical human cell has
50% protein
40% lipids
10% carbohydrates
Cell made of
building blocks
Building blocks
Carbon chains
Sugars
Amino acids
Sugar + base
Building blocks make
Macromolecules
Macromolecules
Lipids
Complex carb
Proteins
Nucleic acid (RNA / DNA)
Supramolecular assemblies
Membranes
Ribosomes
Chromosomes
Organelles
Nucleus
Golgi
ER
Mitochondria
DNA (and mRNA) have instructions to make
proteins and enzymes
What is key to life?
Regulation
Respond to environment
Make and break molecules
Generate energy
Maintain itself
Glycolysis
Breakdown of glucose to pyruvate
Glucose (respond to enviro) Glucokinase (break glucokinase) Glucose 6 Phosphate Generate energy Pyruvate
Central Dogma
Transcription - Transcriptional control RNA processing and stability Translation - Translational control Protein process Protein - Protein activity and stability
Transcriptional control
Determines when and in what cells a gene is transcribed to produce mRNA.
What is the 1st step to determine how many individual proteins are made in a cell?
Transcriptional control
Why is a brain cell different from a heart cell?
1,000 to 2,000 genes are unique to a specific cell type
Transcription
Process where a DNA sequence is copied (transcribed) into an RNA
molecule.
A gene is said to be what when transcribes?
Turned on
or
expressed
If a gene does get transcribed, it is used
to make a protein (expressed).
If a gene is not transcribed in a cell..
Can’t be used to make a protein in that cell
Pancreatic b cell
Insulin gene
Transcription
Translation
Insulin
Pancreatic b cell
Glycogen synthase gene
won’ t make protein
Insulin
Liver cell
Insulin gene
No protein made
Liver cell
Glycogen synthase gene
Transcription
Translation
GS synthase
How many bp of DNA in gene?
3.2 billion
What are Transcription factors?
protein binding to a specific
DNA sequence and control the rate of transcription (DNA
to RNA).
What are key elements of a gene?
Regulatory regions
Transcribed region
Promoter
DNA sequence at which transcription factors bind and recruit RNA Polymerase.
Regulatory regions
Promoter
Determines if and how much a gene is transcribed
contains short sequences that transcription factors bind to.
Transcribed region
Sequences of DNA that are
copied into RNA (transcribed).
The transcribed RNA (pre-mRNA) is processed so..
it can be translated (e.g. intron sequences are removed - splice).
gene is only expressed when both
activator transcription factors are present
and the repressor is absent.
