Life at a cellular level. Flashcards
What is a prokaryotic cell?
Bacteria. No membrane bound structures. No nucleus / mitochondria. DNA chills.
What is a eukaryotic cell?
Found in humans and plants. Has membrane bound structures, and a nucleus.
what is a multipoint stem cell?
A stem cell that can differentiate into one cell type. They can only carry out one or two roles.
What type of cell can differentiate into all cells in the body?
A pluripotent embryonic stem cell.
How is differentiation caused in stem cells?
changes in Gene expression. e.g cell fusion.
What is the term for programmed cell death?
Apoptosis
what does apoptosis, programmed cell death do?
It controls multicellular development.
What is the term for the rapid reproduction of cells?
Proliferation.
What is the plasmalemma ?
Just another word for the cell membrane.
what does amphipathetic mean? (in terms of cell membranes)
Hydrophobic head, hydrophilic tail.
Name 6 functions of the cell membrane?
1) transport
2) enzymatic activity
3) signal transduction receptors
4) intercellular joining
5) cell to cell recognition.
6) attachment to cytoskeleton and extracellular matrix.
what is endocytosis?
The uptake of big things. by invaginating and forming a vesicle.
what is exocytosis?
Proteins that are packaged in golgi network. Vesicle breaks off and travels to cell membrane. e.g regulates secretion.
what is a tight junction.
Two cells sealed together, with no gap. It creates a physical barrier, is dependant on calcium.
Where are tight junctions found?
In the intestines, kidneys, blood brain barrier.
What is an adherens junction?
Links actin filaments in two different cells.
what is a desmosomes?
links keratin filaments in two different cells.
What is a Gap junction?
it links two cells but forms a channel which is constantly open. It allows cell to cell communication.
Where are gap junctions found?
Heart muscle, liver, pancreas.
What is connexions?
6 subunit membrane proteins.
How does disease effect cell adhesion?
Tight junctions can be damaged, e.g. a tumour can break off its original tumour and spread to other parts of cell to recolonize.
What is contact dependant cell signalling?
Requires membrane bound signalling molecules.
Describe paracrine cell signalling.
Receptors from cells target can target more than one localised cells. They use a local mediator.
What type of cell signalling involves a neurone and a synapse.
Synaptic cell signalling.
What type of cell signalling can provoke responses around the whole body by releasing signalling molecules into the blood stream?
Endocrine.
What is the inner membrane of the mitochondria called?
The cristae.
What happens in the mitochondrial matrix?
Calcium binding sides and oxidation of foods.
What is the purpose of the cell cytoskeleton .
It maintains shape and support. It also moves organelles.
what are the four main elements in the body?
H O N C
How are the ten structural elements required by the body gained by the body?
Must intake them through diet.
What happens if proteins do not have the ten structural elements?
They may have the wrong shape and function.
What type of both is the basis of most molecules?
The Carbon bond. - they can form single bonds, double and triple.
What is a chiral carbon?
A carbon with four different groups coming off it.
What is the left mirror image and the right mirror image of a chiral carbon called?
Laevo (left) and dextro (right)
What are the two laws that govern energy changes?
1) Energy cannot be created or destroyed, just converted from one form to another.
2) All energy changes lead to more disorder in the universe. (increase in entropy)
Do cells like order or disorder?
ORDER!
How do cells maintain order and how does it affect the surrounding environment?
Cells perform chemical reactions to get more ordered, but release heat into the surrounding environment which causes it to be more disordered.
Does DeltaG need to be positive or negative for a spontaneous reaction?
Negative. (The reaction releases energy)
What does a spontaneous reaction need.
Decrease in enthalpy or increase in entropy.
Do biological processes have positive or negative delta G?
Positive, as they want more order.
What is reaction coupling?
it is used to carry out thermodynamically unfavourable reactions. It involves catabolic reactions breaking stuff down and requiring -deltaG, paired with anabolic reactions building stuff up requiring +deltaG.
Why can’t biology reaction pathways reach equilibrium?
because the products of one are used in another reaction.
