Cell Function And Hoeostasis Flashcards
What is the role of the nucleus
Largest organelle all cells but red blood cells contains genetic material
What is the role of the plasma membrane
Controls the passage of the substance in and out of the cell regulating environment
What is the role of a ribosome
Synthesises protein from amino acids using RNA templates
What is the role of mitochondria
Makes all our energy -involved in aerobic respiration with o2 and ATP
Centrioles
Produces cellular spindles in mitosis as well as making micro tubules
Chromatin
Helps compact dna from longer strands into smaller packages as part of mitosis
Lysosome
Small membranous vesicles containing enzymes
Golgi apparatus
Synthesised protein are packed and stored here
Endoplasmic reticulum
Smooth- involved in making lipids breaking down co2 and storing calcium
Rough- ribosomes on its surface to make and modify proteins
What are the 3 ways that substances are moved through the cellular membrane and in and out of the cell
Diffusion
Osmosis
Active transport
Describe osmosis
Movement of water down a concentration from an area of high concentration to low concentration
Describe diffusion
Movement of molecules from an area of high concentration to an area of low concentration
Active transport
Transport substances up the concentration gradient requiring energy and carriers
Eg sodium/ potassium pump
Potassium levels higher in the cell and sodium levels higher outside the cell
Particles are transported through phagocytosis
What are the 6 different cell actions
Reproduce
Nourishment
Movement
Excretion
Growth
Respiration
Role of red blood cells
Carry oxygen
Kindney tubules cells roles
Controls water and salt excretion
Kindney tubules cells roles
Controls water and salt excretion
Cardiac cells roles
Contract and controls heart pumping
Cartilage function
Structural support
Neurone function
Conducts electrical impulse (message )
Sperm
Convery genetic material for reproduction
Describe cellular tissues
Groups of similar cells are tissues
What are the 4 basic tissue types
Connective tissues - binding supporting protecting eg cartilage, blood, bone
Epithelial tissues- cells forming continuous sheets often lining body cavities eg skin gut lining and glands
Muscle tissues-skeletal muscles under voluntary control attached to bone for motion/posture
Smooth muscles forming walls of tubes e.g airways, blood vesicles, gut , bladdder ,
Cardiac muscles under involuntary control causing heart to pump
Nervous tissues- Neurone conduct electrical impulses throughout the body eg brain and spinal cord to control body.
How is an organismal made
Group of similar cells= tissues
Group of tissues = organs
6 levels of organisation
Organs - grouping of 2 or more tissues types into recognisable structure with a specific function
System- collection of related organs with a common function
All the systems makes an organismal
Cell suicide apotosis
Cell damage/disease
Necrosis
Lifecycle of most cells
Some continuously replaced
Continuous apotosing and replaced by mitosis
Gut epithelium -turnover 3 days
Skin epidermis-turnover 2-4 weeks
Some cells never replaced they die eg. Muscles and nervous system 50 percent of cells die by the time we are old
Stages of apoptosis
Normal cell
The cell shrinks and chromtins condenses
Membrane start blebbing organelles disintegrates
Nucleus and organelles collapse membrane continue to bleb
Apoptotic bodies form
Macrophages phagocytose apoptotic bodies
Problem with aging
Mitosis slows down so cells that die are not replaced leading to signs of aging
Reduced numbers of immune cells lead to increased risk of infection
Problems with apoptosis
It can increase in some cells causing diseases eg alzheimer where valuable nerves cells die more quickly
Apoptosis can stop causing cells to over divide and form tumours
What is homeostasis
Organism is in homeostasis when conditions in the internal environment are maintained within physiological limits.
When homeostasis is disturbed illness may result. Body fluids and cells are not bought back into homeostasis. Death occurs.
What must be kept constant to protect the cells
Chemical constitution eg glucose, ions, ph
, temperature,
osmotic pressure, eg water and solute concerntratuons
o2/ co2 levels
How does homeostasis work
Receptors cable of detecting changes in body
By having control systems- to initiate corrective measures. Usually a nerve centre
Effectors carry out corrective measures
Negative feedback
Response reverses original stimulus - reworks normal levels
Positive feedback
Response enhances original stimulus eg continues to reinforce the original stimulus
