Cells and tissue Flashcards
What are cells?
Basic living units of tissue and each specialise to perform essential functions
What is a plasma membrane?
Outer part ot the cell
What is the structure of a plasma membrane?
It has two layers of lipid molecules known as a lipid bilayer
The hydrophilic heads which are attracted to water face outwards towards the fluid inside and outside of the cell
The hydrophrobic tails face intowards towards either other
Proteins in and around the lipid bilayer form ion channels, carry substances through and act as a marker for receptors and faciliate cellular function
What is passive transport?
When the concentraion of a substance is higher one one side of the cells membrane, molecules move by osmosis or diffusion through the membrane without using energy
What are transport vesicles?
Membrane sacs that transport to and from the plasma membrane
What is active transport?
When the cell needs to move molecules to an area of low concentration from an area of high concentration, it used channels or carriers in the cell membrane. This uses energy
What is osmosis?
Diffusion of water across a cell membrane
How does osmosis happen?
It depends on the concentration of the solution around the cell
In an isotonic solution e.g., blood, the intake and output of water is balanced
In a hypotonic solution, there is greater concentration of water outside the cell. The cell swells and may even burst as water flows in
In a hypertonic solution, there is great concentration in the cell and water flows out and the cell shrinks
What is diffusion?
The movement of substances due to their kinetic energy
How does diffusion happen?
The selective permeability of the plasma membrane supports the existence of a concentration gradient which means differences in the concentration of chemicals between one side of the membrane and the other.
In net diffusion, substances move from an area of high concentration to low
In simple diffusion, lipid-soluable substances move through the lipid-bilayer
In faciliated diffusion, substances cross the membrane with assistance from ion channels and carriers
What are organelles?
Structures inside the cell
What do organelles do?
Perform cellular functions
What is cytoplasm?
Includes all the cellular contents between the plasma membrane and nucleus
What is the cytoskeleton?
A network of protein filaments that extend through the cytoplasm
They provide structural support for the cell and generate movement
What is smooth ER?
Lacks ribosomes
Where lipids are synthesised.
What is rough ER?
Studded with ribosomes
Manufacture membrane-bound proteins.
What is the golgi complex?
Consists of flattered sacs called cisterns that recieve proteins from the rough ER
Proteins are modified, sorted and packaged for transport
What are lysosomes?
Capsules that contain digestive enxymes that breakdown substances consumed by the cell
What are peroxisomes?
Process and neutralise toxins
Metabolise long chain fatty acids
Contribute to energy function
What are proteasomes?
Contain protease that degrade unneeded, damaged and faulty proteins
What is the nucleus?
Consists of a nuclear envelope and pores which control the movement of substances between the nucleus and cytoplasm
Contains nucleoli which produce ribosomes
Contains DNA and chromosomes
What is mitrochrondria?
Consists of a smooth outer and inner membrane containing folds called cristea
It has a fluid filled sac called the matrix
It uses oxygen to produce ATP
ATP is the molecule cells use for energy
What are ribosomes?
Synthesis proteins
What are cillium?
Hair like projections
What is a flagellum?
Sperm cells have them to project them foward
What is microvilli?
Folds to increase surface area
What is the centrosome/centrioles?
Responsible for cell division
Draw and label a cell
Watch https://www.youtube.com/watch?v=6mgkoqcm6Sg&t=398s
