Growth and Development Flashcards
(33 cards)
what does hypertrophy mean
individual cells grown larger in size
what does hyperplasia mean
individual cells divide and grow in number
describe how single cells can become
what does the term allometry mean
is a biological term that explains the characteristics of creature that change in size
explain myostatin muscle mutation and give an example of one
it is a hypertrophy mutation where body fat is reduced and body mussel is increased, an example is double-muscled cattle
where do you find totipotent stem cells
zygote
where do you find pluripotent stem cells
embryo ( can become any cell)
where do you find multipotent stem cells
in adults ( can become cells within a specific tissue)
explain how stem cell become differentiated
through differentiation where specific genes in the DNA is turned on and off, leading the determination of a cells structure and function
despite having the same DNA explain why a mussel cell and a neuron express genes for different things
because the genes in each cell are active for that specific role
A muscle cell expresses genes for actin and myosin (contractile proteins).
A neuron expresses genes for neurotransmitter synthesis and receptors.
how is differentiation guided
it is guided through external factors such as growth factors and specialized proteins that bind to receptors on the cell
name the growth factors that effect cell differenation
palleted derived growth factor - stimulates division and development with in blood vessels and connective tissue
nerve growth factor - promotes survival and differentiation of neurons
epidermal growth factor -stimulates growth and division of skin and epithermal cells
what is the function of growth factors
to influence which genes get turned on and off steering the stem cell down a particular path
how do growth factor signal to cells
through tyrosine kinase receptors on the cell surface
name the processes which takes place when growth factor signaling
1- ligand binding- the growth factor binds to its specific receptor on the stem cell membrane
2-receptor dimerization -two receptor molecules pair upon binding
3-autophhosphorisation -Each receptor phosphorylates tyrosine residues on the other
4-Activation of signaling pathways-
These phospho-tyrosine sites act as docking stations for intracellular proteins.
This triggers signaling cascades like the MAPK pathway or PI3K-AKT, which travel to the nucleus.
5- Gene expression changes
These pathways activate transcription factors that turn specific genes on/off.
This alters the cell’s behavior—pushing it to divide, differentiate, or migrate.
summaries the specialization of stem cells
Growth factors (like PDGF, NGF, EGF) bind to tyrosine kinase receptors.
These trigger intracellular signaling cascades.
The cell selectively expresses certain genes.
Over time, this locks in a specific identity (e.g., neuron, muscle, skin cell).
explain intercellular communication
how cell communicate their actions by sending and receiving signals
what are gap junctions
small tunnels made up of proteins called conextins, these create direct channels for exchanging ions
name the key features of ap junctions
fast signaling
allows synchronization of cell activities
what are surface signals
physical contact between cells
involving membrane-bound proteins or glycoproteins on the surfaces of cells that interact directly when cells touch.
what are the chemical methods of intercellular communication
Cells can secrete chemical signals (ligands), such as hormones, neurotransmitters, or cytokines.
autocrine
endocrine
paracrine
what is autocrine signaling and an example of it
autocrine signaling is when the signal travels to the same cell that released it
example- T-cell secreting IL-2 to stimulate its own growth
what is endocrine signaling and an example of it
when the signal travels further through the bloodstream
example-Insulin from pancreas affecting muscle and liver
what is an example of paracrine signaling and an example of it
when the signals travels to a cell near by
example -Growth factors like PDGF during wound healing
