Physiology Flashcards
What does it mean by the plasma membrane being fluid?
It can change its shape easily. Many proteins in the membrane can diffuse laterally, but many are anchored so it is important to realise that many proteins are not distributed equally within the cell membrane.
What is the structure of a plasma membrane ?
It is a bio-molecular layer of amphipathic phospholipid molecules with their hydrophilic heads at the outer and inner surfaces and their hydrophobic fatty acid chains facing towards the middle
What are found in the plasma membrane ?
Cell attachment proteins
Receptors
Enzymes
Channels
Transporters
What is cytosol made of?
Proteins
Carbohydrates
Electrolytes
It has fluid and gel-like properties
What are the common features of a eukaryotic cell?
Outer membrane
Cytoskeleton
Cytosol
Membrane bound organelles
Inclusions
What is the cell membrane permeable and non-permeable to ?
It is permeable to oxygen,water, hydrophobic molecules and small molecules and non-permeable to charged molecules like sodium and potassium.
What is the function of the plasma membrane ?
It separates the cytoplasm from the outside environment.
How can an organelle be defined?
Small membrane bound organ that has a specific function and structural organisation that is important to maintain life.
What are examples of membrane bound organelles?
Mitochondria
Rough endoplasmic recticulum
Smooth endoplasmic recticulum
Golgi apparatus
Lysosomes
Nucleus
What are inclusions?
Inclusions in a cell are small, non-living substances or particles found inside the cell.
Name some Inclusions in the cell?
Glycogen granules
Lipid droplets
Pigments
What is the cytoskeleton?
The cytoskeleton is a network of protein fibers inside a cell that gives the cell its shape, supports it, and helps it move. It acts like the cell’s “skeleton” and “muscles,” providing both structural support and flexibility.
What does the cytoskeleton do?
The cytoskeleton also plays a role in transporting materials within the cell and helps organize its internal components.
What is the cell membrane permeable to?
small hydrophobic molecules
water
oxygen
What defines a eukaryote?
Any cell or organism that possesses a clearly defined nucleus
What is a plasmalemma?
It separates the cytoplasm from the outside environment , that forms a selectively permeable barrier
What is cell membrane impermeable to?
charged ions
What can be found in cytoplasm ?
organelles and inclusions
What does the mitochondria do?
produces energy production(energy house)
What does the rough ER do?
synthesises proteins
What does smooth ER do?
synthesise lipids and cholesterol
and detoxifies
What does Golgi apparatus do?
modification and packaging of secretions
What do lysosomes do?
hydrolytic enzyme for intracellular digestion
What does the nucleus do ?
contains genetic code
What is an example of inclusions?
adipose cells in brown fat
What are microfilaments composed of?
2 actin strands
What are microtubule composed of ?
alpha and beta tubular that form protofilaments -> form microtubule
What are MAPS?
Microtubule associated proteins
What is dynein and what does it do?
It is an ATPase, that moves toward the cell and drags the membrane of organelles and vesicles along the microtubule
What is kinesin and what does it do?
It is an ATPase, that moves toward the cell periphery and drags the membrane of organelles and vesicles along the microtubule
What is Euchromatin?
DNA that is more dispersed and undergoing transcription
What is heterochromatin?
DNA that is highly condensed and not undergoing transcription
Where does mRNA and tRNA synthesis take place ?
in nucleus
Where does rRNA take place?
in nucleolus(within nucleus)
What do nuclear pores do?
allow the transport of molecules across the nuclear envelope
Where are ribosomes formed?
in nucleolus
What do cristae do and where can they be found?
In mitochondria, they increase the surface area
What does the mitochondria do?
produce ATP through oxidative phosphorylation, and is involved in creating certain lipids and proteins
What do intracellular junctions do?
connect cells to other cells, happens mainly in epithelial cells
What are occluding(tight) junctions?
links cells to form a diffusion barrier and prevents diffusion
aka Zona occludens