Introduction To Cell Biology Flashcards
What is the plasma membrane
It marks the boundary of the cell
It is a phospholipid bilateral which is selectively permeable - hence is regulated the internal cellular composition
It allows the cells to consume ‘food’ and excrete ‘waste’
When does a phospholipid mono layer and bilayer form
Phospholipid monolayer forms when oil comes into contact with water
Phospholipids form bilayers when they contact water alone
Hydrophobic tails exclude water
What do plasma membranes feature
Proteins such as carriers and channels that can transport molecules in and out of cells
Harder for larger or highly charged molecules to pass through the plasma membrane passively
What do prokaryotes and eukaryotes consist
E - nucleus, organelles, several molecules of linear DNA, histones, introns, 3 types of RNA polymerase , 80s ribosomes, monocistronic translation.
P- one moelcule of circular DNA
One type RNA Polymerase
70S type ribosome
Polycistrobjc translation
Name types of prokaryotes and clinical relevance
Eh. Spirillum, spirochete,cocccus,coccobacillus, vibrio,bacillus
Clinical relevance- cause disease such as caries or periodontitis
Transcription and translation can occur simultaneously
Polycistronic - 1 mRNA molecule code for more than 1 pp
cell cycle is continuous
What is the endosymbiosis theory
- Acquisition of mitochondria organelles
- an anaerobic cell derived from an archaeologist with a primitive nucleus
-An aerobic bacterium (protomitochondrion) was incorporated into this cell
-the bacterium evolved into a mitochondrion. - Acquisition of chloroplast organelles
- the anaerobic cell incorporated a photosynthetic bacterium
The bacterium evolved in a chloroplast
What is a cytoskeleton
Provides structural integrity
Allows for locomotion, transport and cell division
Implicated in cellular responses such as mechanosensing
What structural proteins does the cytoskeleton consist of
- Actin filament
- 7nm
- provides structural integrity - stress fibres
Allow for locomotio (actinomyosin bridges) - Intermediate filaments
- 10 nm
E.g lamins, keratins
Provide structural integrity - Tubulin filaments
-25nm
E.g alpha and beta tubulins
Polymerise into microtubules
Responsible for the assembly of mitotic spindle
Segregate organelles to daughter cells
Summarise mitosis
Interphase - dna replication
Prophase- chromosomes spiralise
Metaphase - chromosomes align with their centromeres on the equator and attach to the spindle
Anaphase- chromatids of each chromosome separate into daughter chromosomes and move to opposite piles
Telophase- two nuclei reform at poles
Daughter cells- after cytokinesis two daughter cells result
What is the kinetochore on the chromosomes
The kinetochore is a protein complex which associates with the centromere during cell division. It is where spindle fibres attach during metaphase
Summarise meiosis
DNA replicates
Dna pairs and crosses over of duplicated homologs
The homologs pairs line up on the spindle
There is segregation of homologs at anaphase I
Segregation of sister chromatids at anaphase II
Forms haploid daughter cells
What are viruses
Non living cells
Obligate intracellular parasites- can’t reproduce outside their host cells
Can be a major cause of disease
How do viruses insert genetic info
- endocytosis and fusion for influenza.
- Fusion for HIV virus
- Endocytosis and lysis- adenovirus
- Endocytosis and pore formation -poliovirus
What are prions
Protein infectious agent
No nucleic acid genome
Prion disease known as spongiform encephalopathies
- post mortem apparence of brain large vacuoles in the cortex and cerebellum
Heat resistant and UV IRRADIATION RESISATNT
Issues with irreversible contamination of surgical instruments
What is neurodegenerative spongiform disease caused by
Caused by conversion of PrPc to PrPsc
Results in brain lesions
Kuru - neurodegenerative disease affecting Papua New Guinea Due to cannibalism
