Unit 4 Cell Communication And Cell Cycle Flashcards
How is the process of distance communication different from the process of communicating during cell-cell contact?
Structural modifications of the cell membrane and cell wall allow cells to send chemical signals directly into adjacent cells.
What is a signal transduction pathway?
(how does it cause a cellular response)
A signal transduction pathway is when the signal molecule a ligand binds to the receptor located on the cell surface or inside the cell that triggers events (a signal cascade) inside the cell, to invoke a response.
Why do cells use signal transduction pathways? why is it so important?
to regulate cell communication in a wide variety of ways such as growth, secretion, and gene expression.
without it, it would make it impossible for cells to respond to the information given
How does negative feedback maintain homeostasis?
Negative feedback maintains homeostasis by reducing the result of a reaction to bring the system back to a stable state. a hormone decreases to cause another hormone to decrease
ex: Blood sugar regulation (insulin lowers blood glucose when levels are high
once an infection is under control negative feedback is activated to lower your body temperature
How does positive feedback affect homeostasis?
example?
Positive feedback maintains homeostasis by amplifying the result of a reaction to make it occur more quickly. a hormone increases to cause another hormone to increase
ex: glucagon raises glucose levels when they are to low
The hotter you get the more you sweat
The more growth hormone you have the taller you get
What is the role of interphase?
What occurs during interphase?
allows newly divided cells the opportunity to grow, maintain normal cell function, and prepare for division.
cells grow, replicate DNA, and prepare for division.
What is the role of mitosis?
What occurs during mitosis?
Mitosis plays a role in growth, tissue repair, and asexual reproduction.
During mitosis genetic information is transferred.
What is the role of checkpoints in regulating the cell cycle?
Checkpoints help determine whether the cell is ready to progress through cell division.
How are proteins are involved in checkpoints?
Proteins are used to activate or inhibit cell cycle activities.
What happens if the cell cycle is disrupted?
Disruptions to the cell cycle may result in cancer and or programmed death (apoptosis)
what are the three stages of signal transduction?
Reception: The signal molecule (ligand) binds to the receptor and changes the shape of the receptor protein in some way
transduction: The activated receptor triggers a chain of biochemical reactions in the cell. many different enzymes are involved. the entire reaction is called a signal cascade.
Response: cells respond to the messages and changes are made to the cell’s behaviour
describe Autocrine signalling
is it short or long
usually involves helps with?
a cell signals to itself, releasing a ligand that binds to receptors on its own surface (or, depending on the type of signal, to receptors inside of the cell).
binds to itself
short
cytokines and neurotransmitters
helps regulate blood pressure, nervous system function, and reproduction
describe cell to cell communication
it involves cells interacting with one another in two forms
communication by special channels between adjacent cells
cells bind to and communicate with each other because they have complements proteins on their surface
Describe endocrine signalling
is it short or long
it’s a signal that is carried in the bloodstream to target cells (long distances) Mostly involves hormones or cytokinesis (small proteins that are crucial in controlling the growth and activity of other immune system cells and blood cells)
maintains homeostasis by producing hormones and secreting them into the blood stream
long
Describe paracrine signalling
is it short or long
usually involves
helps with
allows cells to communicate with each other by releasing signalling molecules that bind to and activate surrounding cells. (signals move through diffusion)
short
cytokines and neurotransmitters
helps regulate blood pressure, nervous system function, and reproduction
what’s a target cell
a specific cell that receives and responds to a message
what happens in G1 phase when is their checkpoint and what do they check for?
the cell accomplishes most of its growth. they get bigger in size and make most of their organelles and proteins including RNA, centromere, and parts of the centrosomes.
checkpoint is at the end of G1 Phase
Check For…
Cell Size
Nutrients
Growth factor
DNA damage
what happens in S phase when is their checkpoint and what do they check for?
occurs during interphase responsible for DNA replication.
what happens in G2 phase when is their checkpoint and what do they check for?
The cell grows more and makes more organelles and proteins. begins to reorganize its contents in preparation for mitosis.
check for DNA damage and DNA replication
How can cells communicate over varying of distances using different types of signalling
Depending on the distance cells use different types of signalling
what is quorum sensing
a process of cell to cell communication that allow multiple bacteria to share information
what is a cellular response
the way that cells respond to signals in their environment.
Explain how a change in the structure of any signaling molecule affects the activity of the signaling pathway
by mutations and any mutation that alters the ligand/receptor can lead to incompatibility, the receptor won’t be able to properly shape change resulting in an inactive transduction pathway
What is the function of a ligand? Give an example
Small molecules (signal molecules) that attach to the receptor site to start a signal transduction pathway
example steroid hormone
How does Apoptosis help the overall health of a multicellular organism?
apoptosis is the process of programmed cell death. it’s used to eliminate unwanted cells such as
cancerous and virus-infected cells, and maintains balance in the body by a death signalling molecule being attached to the receptor.
what happens in the M checkpoint?
checks if the spindle fibres are attached to the chromosomes
What happens to a cell causing it to stop at G0?
Give an example of a cell arrested at G0.
The cell has received signals to stop dividing or they don’t meet the requirements of the checkpoints such as a lack of nutrients
Nerve cells remain at G0
Describe what happens if the enzymes involved in the transduction pathway are denatured
Sometimes changes in environmental conditions such as temperature or PH around the cell causes denaturation of proteins and enzymes, which result in pathway disruptions. It eventually leads to cell death since the cells fail to respond to the change effectively.
Describe what happens if an inhibitor is introduced at the receptor site
If an inhibitor is introduced to the receptor site then the all activates stop the signal is inhibited
Describe the signal transduction pathway of a protein hormone and steroid hormone
see picture
Describe the function of a cascade in a signal transduction pathway.
a signal cascade is a series of chemical reactions that occur within a cell when initiated by a stimulus and its function is to transmit biochemical information between the cell membrane and nucleus by amplifying the signal by activating the protein molecules and the secondary messengers in the cell
Describe the function of a second messenger in the signal transduction pathway.
Second messengers are small molecules and ions that pass on information (signals) received by cell-surface receptors to effector proteins.
