L1 - Introduction Flashcards
The UK population is _________ faster than it is ________
Ageing
Growing
UK Population growth
WHOLE
+65
+85
3%
12%
18%
What percentage of the UK welfare budget is spent on pensioners
55%
Who proposes the theory of epigenesis
Aristotle
345 BC
What is the theory of epigenesis
Step wise and progressive development of an organism through the development of new strucutres and formations
Was Aristotles theory accepted straight away
No, was conceptually hard to grasp
Who proposed the theory of preformationism
Hartsoeker
1965
What is the theory of preformationism
The organism is already fully formed it just needs to be able to grow
3 major points about cell theory
All organisms composed of one of more cells
The cell is the most basic unit of life
All cells arise from preexisting cells
Who proposed the cell theory
Robert Cooke
Who proposed the Germ plasm determinants theory
Weissman - 1880
Describe the germ plasma determinants theory
Germ cells contain a full set of determinants
Somatic cells on the other hand only contain a subset of the determinantns
So when cells dif. they inherit a certain set of factors which determines their fate
Who performed the experiement which provided supporting evidence for Weissmans Germ Plasm theory
Roux
Ablation experiement
Describe the methods used by Roux in his ablation experiment
What was the main oberservation
What theory did this appear to support
Took a blastula at the two cell stage and ablated one of the cells
At the end of development the embryo was only half formed
Supported Weissmans germ plasm theory
Who proposed the induction theory - what were the methods of his experiment
Driesch
Instead of ablating one of the cells at the two cell stage he separated them
What were Drieschs main observations from the separation experiment
What were Drieschs main conclusions from the separation experiment
Each of the sep cells lead to formation of a full embryo
Cell-cell communicaiton was disrupted
Each of the cells MUST contain the full set of determinants but only a CERTAIN SUBSET is expressed
The expression of the subset of determinants is determined by cell-cell communicaiton
What are the two types of gene expressed in cells
Ubiquitous - hosuekeeping genes
Tissue specific genes
What are the two ways in which gene expression is controlled
Intrinsic or extrinsic
Give an example of intrinsic cues acting
E.g. the mother cell differentiating into a specialised cell with no external influence
What is cell intrinsic also called
Cell Autonomous
What is an example of extrinsic cues
What does this require
One cell type induing another cell type to a certain cell fate
Cell cell communication
What are the 5 ways in which cells acquire new properties
Division Adhesion Migration Death Shape
What are the two ways in which cells are able to divide
Can either be symmetrical or non symmetrical
What are the three ways in which non symmetrical division is able to take place
Segregation of cytoplasmic determinants
A membrane bound determinant being confined to one edge
An ECM linked determinant being confined to one edge of the cell
What is paracrine signalling
One cell type secreting a factor (ligand) which acs on a receptor of a different cell leading to a cascade of events
Autocrine
One cell type secretes a ligand which then acts on the SAME CELL OR SAME TYPE OF CELLS
Juxtacrine signalling
Cell cell communication which occurs over a short distance as both ligand and receptor are tethered to the membrane
Signal reception requires
Cell to be competent
What are instructive signals
Initiate a new program
What are permissive signals
Provides a favourable environment for a specific program
What are morphogens
Instruct different fates dependent on their concentrations
Describe reception
The ligand binding to the cell surface receptor and activating it
Describe transduction
Receptor activation induces the transduction of the signal from the membrane to the nucleus via a cascade of second messenger activation
Describe response
A transcription factor is activated and this induces the transcription of a specific set of genes
From which germ layer does the following tissue/organ arise from
Skin cells
Ectoderm
From which germ layer does the following tissue/organ arise from
Neural
Ectoderm
From which germ layer does the following tissue/organ arise from
Cardiac muscle
Mesoderm
From which germ layer does the following tissue/organ arise from
Alveolar cell - lung
Endoderm
From which germ layer does the following tissue/organ arise from
thyroid
Endoderm
From which germ layer does the following tissue/organ arise from
Muscle
Mesoderm
From which germ layer does the following tissue/organ arise from
Blood cell
Mesoderm
From which germ layer does the following tissue/organ arise from
Gut
Mesoderm
From which germ layer does the following tissue/organ arise from
Sperm and Egg
From the germ layer
From which germ layer does the following tissue/organ arise from
Pigment cells
Ectoderm
What is tissue homeostasis
The balance between cell renewal and cell death
What is cell renewal through
Stem cell population
Too much renewal of cells causes
Cancer
Too much cell death =
Tissue aging and degeneration
