Lecture 1 Flashcards
What are the domains of cellular life?
The domains of cellular life are bacteria, archaea, and eukaryota
What components make up the nucleus?
nuclear envelope, nuclear lamina, nuclear pores, nucleolus, and nucleoplasm
what components make up the nuclear envelope and what are their functions?
The inner nuclear membrane which stabilizes the nuclear envelope
The outer nuclear membrane is continuous with with rER
What is the structure of the nuclear lamina?
Thin sheet like meshwork that is below the inner nuclear membrane.
Hutchinson-Gilford progeria syndrome and other laminopathies?
Mutation in the lamin proteins. They are a type of intermediate filament in the nuclear lamina.
Describe the function of the nuclear pore complex?
This complex allows for the transport of molecules between the nucleus and cytoplasm
Purpose of the nucleolus?
It is the site of ribosome production
What zones make up the nucleolus and what are their roles?
Fibrillar center- pale staining and contains rRNA genes
Fibrillar material- transcription of rRNA genes
Granular material- initial ribosomal assembly
What is chromatin?
Chromosomes that are in various degrees of uncoiling
Normally packaged into nucleosomes (wrapped around histones)
What are the two types of chromatin and what are their characteristics?
Euchromatin- lightly stained, less condensed, more transcriptionally active
Heterochromatin- dense staining, more condensed, less transcriptionally active
Describe the nucleosome
Fundamental structural unit of chromatin
eight histone molecules (octomer) 2 loops of DNA around the core of the octomer
found in both types of chromatin
What three parts make up the chromosome?
Centromere, telomere, and the replication origin
What are the purposes of the three parts of the chromosome?
centromere- helpful during mitosis
telomere- at the ends of the chromosomes. they are repeated sequences that allow for replication
Replication origin- locations were DNA replication begins
Clinical importance of telomerase enzyme?
cancer and aging
What is the structure and function of the ribosome?
The ribosome is made up of two RNA subunits and is used for translation
What are the two different types of ribosomes?
membrane-bound and free
Where are membrane bound ribosomes and what proteins do they synthesize?
They are found in the rER and they synthesize lysosomal proteins, secreted proteins, and PM proteins
mRNA contains an ER signal sequence!
typically secreted
Where are free ribosomes located and what proteins do they synthesize?
They are unattached to any membrane and the mRNA does not have an ER signal sequence
They synthesize nuclear proteins, mitochondrial proteins, cytosolic proteins, and peroxisomal proteins
typically keep in cytosol
What are the two regions of the ER and what are their functions?
Smooth ER- synthesis of lipids and detoxification
Rough ER- to synthesize proteins destined for the PM, lysosomes, or secretion. site of post-translational modification and folding
What kinds of cells is the rER found in abundance?
cells that specialize in protein synthesis
Ex: secretory cells
characteristics of the sER
region of the ER that does not have any bound ribosomes.
Functions of the sER
seen in large amounts in cells that specialize in lipid metabolism.
Ex: cells that secrete steroids
Plays a major role in detoxification.
Ex: Large amount in liver!
Cytochrome P450 system
Also functions to sequester calcium
Ex: muscle cells
What is the structure of the golgi?
Complex of flattened membrane enclosed cisternae
Located next to the nucleus and centrosome
Has a cis face and a trans face
cis face and trans face of the golgi?
Cis face is the entrance into the golgi (Cis golgi network)
trans face is the exit of the golgi (trans golgi network)
