homeostasis and cell’s Flashcards
what is homeostasis
maintenance of a stable internal environment so that your internal environment is kept in a state of dynamic equilibrium
what are factors of homeostasis
temperature regulation, regulations of hormones, maintain blood pressure
why is it important to maintain the right core body termperature and blood ph
temperature and pH affect enzyme activity, and enzymnes control the rate of metabolic reactics
why is it important to maintain the right blood glucose concentration
because cells need glucose for energy and blood glucose concentration affects to water potential of blood
why does the rate of metabolic reactions increase when the temperatures increased
more heat means more kinetic energy, the molecules will move faster, meaning they are more likley to collide with the enzymes active sites.
if the temperature gets too high why does the reaction eventually stop.
the rise in tempertaure makes the enzymes molues vibrate more. If the temperature becomes too high , the vibration brakes some of the hydrogen and ionic bonds which hold the enzyme in its shape. the active site changes shape and the enzyme and substrate no longer fit. enzyme is denatured
if blood ph is too high or low why do reactions eventually stop
enzymes will denature due to the hydrogen and ionic bonds breaking, the active site changes shape and the substrate will no longer fit, the reaction can not occur.
how would you calculate the pH
calculated based on the concentration of hydrogen ions (H+) in the environment
if it is a more acidic environment, does this mean there is a high concentration of H+, or a low concentration
as there is a greater concentration of H+, the lower the pH will be, meaning it is a more acidic environment
why is it bad if blood glucose concentration becomes to high
if it is too high, the water potential of blood is reduced to a point where water molecules diffuse out of cells into the blood via osmosis, this can cause the cells to shrivel up a die.
if blood glucose concentration is too low why are cells unable to carry out normal activities
because there isn’t enough glucose for respiration to provide energy
explain the negative feedback loop
- receptors detect when a level is too high or too low
- the information is communicated via the nervous system or the hormonal system to effectors.
- the effectors respond to counteract the change, bringing the level back to normal
fill in the blank
normal level -> level changes from normal -> receptors detect change -> -> effectors respond -> level brought back to normal
communication via nervous or hormonal system
why do we have multiple negative feedback mechanisms
means you can actively increase or decrease a level so it returns to normal e.g you have feedback mechanisms to reduce your body temperature and also have mechanisms to increase it.
is this feedback loop negative or positive?
normal level -> normal level changes -> receptors detect change -> communication via nervous or hormonal system -> effectors respond -> change amplified
positive feedback loop
what is positive feedback
the mechanism that amplifies a change away from the normal level
when is positive feedback useful
it is useful to rapidly activate processes in the body
blood glucose concentration is monitored by cells in the what
pancreas
the hormonal system controls blood glucose concentration using which two hormones
insulin and glucagon
What is the role of the nucleus
Contains nucleolus which has cell DNA. Directs all metabolic activities
What is the role of the smooth endoplasmic reticulum
Synthesises lipids and steroid hormones
What is the role of the fought endoplasmic reticulum
Studded with ribosome which synthesis proteins
What is the role of the Golgi apparatus
Where proteins are packaged into membrane bound vesicles
What is the role of the mitochondria
Powerhouse of cell. Produce ATP
What is the role of the cell membrane
Controls what goes in and out of the cell
The cell memebrane is a protective layer that helps with what
Protection, transportation, communication
What is the cell membrane primarily made up of
Phospholipids
The phospholipids have a polar head, does this mean they are attracted to or replied from water
Attracted to
The phospholipids have a non polar head, what does this mean
It repels water
The cell membrane houses other molecules such as what
Proteins, carbohydrates and cholesterol
By the does cholesterol in the cell membrane help with
Communication about other cells
Is diffusion a passive or active process
Passive, no energy is needed
Is active transport a passive or active process
Active, energy is required
Is osmosis a passive or active process
Passive
What is phagocytosis
Large particles are taken in by the cell
What is endocytosis
The process of taking material into the cell by means of pockets in the membrane
What is exocytosis
The removal of large amount of materials from the cell
What is pinocytes
The process by which certain cells can engulf and incorporate droplets of fluid
What are the two phases or DNA replication called
Transcription and translation
What is transcription
Where DNA is copied to RNA in the nucleus
What is translation
Where RNA is used to create proteins in the cytoplasm
What is homeostasis
Process in place in order to keep the internal conditions of the body constant. This is done through the use of control systems
What factors need to remain constant
Temperature Glucose Ph Toxins Blood pressure
What does the control system consist of
Detector
Control centre
Effector
What is the role of the receptors in the negative feedback loop
Monitors and detects change
What are automatic control systems
Recognise when there’s a change from the optimal conditions, then send a signal so that the levels go back to normal
What does the coordination center do in the negative feedback loop
Interpret the change which has been detected by the receptors and decided what needs to be done about it
What do the effectors do in the negative feedback loop
These are the things which carry out change
What do positive feedback mechanisms do
Take the response further from the norm
What does negative feedback systems do
When ever the level of something gets to high, negative feedback decreases it to return to normal
What is active transport
The movement of particles against the ontration gradient
What is osmosis
The movement of water molecules across a semipermeable membrane
What is diffusion
The movement of particles from an area of high concentration to low contraction
The endoplasmic reticulum is formed by what
An extensive network of membranous canals
Where is the nucleolus found and what is it involved in
Found in the nucleus and involved in the assembly of ribosomes
A small membranous vessicle that constrains digestive enzymes, which part of the cell is being referred to here
The lysosomes
The ribosomes are found free in the cytoplasms, they attack of to what
The rough endoplasmic reticulum
Heat change in the body is detected by what
The hypothalamus
Heat is lost from the body as what
Radiation
What are the four systems of thermoregulation
Integumentary
Cardiovascular
Musculoskeletal
Nervous
Can infants regulate their own body temperature
No
Infants can easily over heat, what serious issue can this result in
Febrile convulsions, seizures
What do baby’s contain brown fat
For extra insulation
Most of the ATP that cells require is produced in the what?
Mitochondria
The movement of carbon dioxide from an area of relatively high concentration to an area of relatively low concentration is an example of what?
Diffusion
The plasma membrane separates the what from the what?
Separates the interstitial fluid from the cytoplasm
The backbone of the plasma membrane is a what belayer
Phospholipid
The watery component of the cytoplasm is called the what
Cytosol
Most of the ATP required to power cellular operations is produced in the what
Mitochondria
What consists of a network of intracellular membranes with attaches ribosomes
Rough endoplasmic reticulum
The control centre for cellular operations is the what
Nucleus
The extra cellular fluid in most tissues is called the what fluid?
Interstitial
What will have to a red blood cell in hypotonic solutions
Swell and burst
The movement of water through a semi-permeable membrane is called what
Osmosis
