Ch 1 Flashcards
(114 cards)
Plasma membrane functions are carried out by ____
Bound transmembrane proteins
Cell to cell communication uses chemical messengers systems that ____into ___fluid
Release secretions into extra cellular fluid
The process to generate membrane potential is
Diffusion of current carrying ions
What is the main difference between smooth muscle vs skeletal muscle?
SM have dense bodies attached to actin filaments
What is the role of rRNA in the nucleus?
Provide a site for protein synthesis
Defective sperm motility is secondary to which cellular component?
Microtubules
Which cellular transport mechanism required the most energy?
Vesicular transport
Desmosomes role in cells?
Forms junctions at epithelial cells
What percentage of human genome are protein encoding?
1.5%
What percentage of non coding proteins regulate coding regions?
80%
Central area of chromosome is called — and distal area is called —
Centromere
Telomere
What is the role of centromere? 2
Spindle apparatus attachment
Maintain heterochromatin
What are single nucleotide polymorphisms (SNP)?
Variant in single nucleotide position and are almost always bialleleuc eg one base different
Occurs mostly in non coding region (only 1% in coding region)
What is copy number variations (CNV)?
Genetic variations consisting of different number of large stretches of DNA eg deletion, duplication
What is epigenetics?
Heritable changes in gene expression that are not caused by variation in DNA sequence
What is a nucleosome?
DNA segment of 147 base pairs long, wrapped around central core protein (histone)
Inactive dense chromatin is called
Heterochromatin
Open, active chromatin is called
Euchromatin
What happens to chromatin during histone acetylation?
Opens up so transcription can happen (methylation condenses and inhibits transcription)
Which residues can be methylated? 2
Lysine
Arginine
What is the role of micro RNA (miRNA)?
Do not encode proteins, they modulate translation of target mRNA
Post transcription silencing of mRNA genes
What is the role long noncoding RNA (LC RNA) 4
- Gene silencing: restricting RNA polymerase leading to physiologic X chromosome inactivation (bind TF)
- Enhancer: expansion of transcription via gene promoters (promote TF)
- Stabilise protein complexes for gene expression
- Facilitate histone/DNA modification
What is the role of free ribosomes?
Cytosol protein synthesis
What is the role of smooth ER?
Steroid hormone and lipoprotein synthesis