cell structure and function Flashcards
what are the difference between prokaryotes and eukaryotes ?
prokaryotes Eukaryotes
No membrane-bound organelles whereas Has membrane-bound organelles
DNA in a nucleoid, not separated from the
rest of the cell whereas DNA separated from the rest of the cell in
the nucleus
Single-celled whereas Can be single-celled or multicellular
Circular DNA with no introns whereas Chromosomal DNA with exons and introns
Smaller whereas Larger
what are the two major forms prokaryotes?
Bacteria
Archaea
do prokaryotes have membrane bound organelles ?
no
how do viruses work ?
fundamentally work by injecting their genetic material [ can be DNA or RNA]
Makes copies of the DNA/RNA
makes the protein it codes for
kills cells by getting too full of virus components and burst open
what are the four major kingdom within eukaryotes ?
animals
plants
fungi
protist
how can an animal cell be defined by its features ?
don’t have a cell wall
don’t have chloroplasts
always multicellular
what are the functions of membranes ?
compartmentalisation
communication
selective permeability
what are the three types of membrane proteins ?
integral
lipid-anchored
peripheral
what is integral membrane protein?
amphipathic
span the membrane
single pass and mulit pass partially embedded
attached to only one side of the membrane
what is lipid anchored membrane ?
found on both membrane surfaces
anchored via covalent bonds to lipid molecules within membrane
what is a peripheral membrane protein ?
- Lack hydrophobic regions
- Do not interact with fatty acid ends of membrane lipids
- Associated with membrane surface
- Electrostatic interactions
- Hydrogen bonding
- Either to other proteins or to polar head groups
What is the functions of membrane proteins ?
transport
ATP production
biotransformation [metabolism ]
receptors
cell-cell recognition
what are the two critical functions of the nucleus ?
contains the cell hereditary info [DNA]
Coordinates and controls cellular metabolic activity
from latin what does reticulum mean ?
Net
what are endoplasmic reticulum’s ?
A system of folded, interconnected membranous vesicles
- Large flattened sac-like structures (cisternae)
- Internal space called the lumen
- Two types – smooth and rough ER
- May account for >50% of the cell’s total membrane content
- Both types of ER involved in synthesis, storage and transport of
biomolecules
describe golgi apparatus
large sac like membranous vesicles , associated vesicles and tubules
what does the golgi apparatus do ?
Involved in packaging and distribution of cell products for internal and external use
- Vesicles budding off ER travel and are accepted by Golgi
- Vesicles budding off Golgi travel to the cell surface or other organelles
what membrane are vesicle membrane similar to ?
plasma membrane
what are functions of vesicles ?
Vacuoles
Lysosomes
Peroxisomes
Transport vesicles
Secretory vesicles
where are largest cell vacuoles found ?
plant
what are function of vacuole?
compartment for storage and transport
what are function of transport vesicles ?
move molecules within the cell
recognise and fuse only with the target membrane
what are the function of secretory vesicles ?
contain material to be excreted from the cell
removal of waste
release of chemical signals
what are the two types of vesicle fusion ?
Full fusion
kiss and run
what is the function of mitochondria ?
site of aerobic respiration and energy production [ATP]
how many membrane does the mitochondria have ?
double
what does the mitochondria matrix contain ?
enzymes
ribosomes
DNA
machinery for producing ATP for the cell
what are the three thing the cytoskleton responsible for ?
cell movement
cytokinesis [cell division ]
organisation of the organelles
what is the cytoskeleton comprised of ?
microfilaments
intermediate filaments
microtubules
what process does stem cells become specialised cells ?
differeniation
what is a pluripotent cell?
can become all cell types except placenta
what is a totipotent cell ?
can become all cell types
what is a multipotent cell ?
can become multiple cell type
what is a unipotent cell ?
can produce one other type of cell and self renew
what is a blastomere type of stem cell ?
- Cells coming directly from fertilised zygote
- Self-renew and become the entire body
- Totipotent
what is an embryonic stem cell ?
Embryonic stem cells
* In the blastocyst (the very early embryo)
- Can not become the placenta (rest of the blastocyst does this)
- Pluripotent
What is an adult stem cell ?
Adult stem cells
* Found in the adult body
- Responsible for repair and maintenance of tissues
- Mostly multipotent, some are unipotent
what are blood cells formed and what from ?
bone marrow and from multipotent haematopoietic stem cells
what are the three main categories of blood cells ?
- Erythrocytes (red blood cells)
- Leucocytes (white blood cells)
- Platelets
what are some of the features of red blood cells ?
- Lack most organelles
- Do not contain DNA
- Limited repair capabilities and lifespan
what type of stem cells are neurones ?
self renewing multipotent stem cells
what three basic cell types does it generate ?
- Neurons
- Astrocytes
- Oligodendrocytes
what are neurones specialised to do ?
transmit infomation
longest and oldest cell in the body
what is spermatogenesis ?
Haploid spermatozoa develop from germ cells in the seminiferous tubules
how is a sperm cell adapted ?
- Head (acrosome & nucleus)
- Tail (undulipodium)
- Small and thin
