Cell structure Flashcards
What are organelles?
Components of cells which have a specific function
What is the function of the nucleus?
Stores DNA and transmit genetic info
Provides mRNA for protein synthesis
Control centre of cell
What is the structure of the nuclear envelope?
It has a double membrane with pores for ribosomes and mRNA
What is chromatin?
The genetic material and condenses into tightly coiled chromosomes
What is the name of cytoplasm in the nucleus?
Nucleoplasm
Do ribosomes have a membrane?
No
What are the main functions of the 2 types of ribosomes?
Free - synthesis proteins for use inside the cell
RER bound - synthesise proteins to be exported for outside use
What is the function of mitochondria?
Aerobic stages of respiration to produce ATP
What is the structure of mitochondria?
Rod shaped, double membrane bound.
What is the difference between the 2 membranes in mitochondria?
Inner membrane has aerobic respiration proteins folded into cristae (increase SA)
What is the function of the mitochondrial matrix?
Contains enzymes for aerobic respiration as well as lipids, ribosomes, DNA
What is the cell surface membrane also known as?
The phospholipid bilayer
What is the cytoskeleton?
Complex protein network of proteins in the cytoplasm
What is the function of the cytoskeleton?
Mechanical strength, maintains shape and movement of organelles
What is the cytoskeleton made up of?
Microfilaments, intermediate filaments and microtubules
What are microfilaments?
Polypeptides forming a mesh . Maintain shape and mechanical strength. Cell movement in smaller cells eg. lymphocytes
What are intermediate filaments?
Interlocking protein fibres anchoring the nucleus which can extend outside the cell so cells can stick together and communicate.
What are microtubules?
Repeating units of tubulin. They are for the movement of substances and organelles in the cytoplasm. Use energy from ATP hydrolysis
What is the structure of centrioles?
Bundles of microtubules perpendicular to each other.
What is the function of centrioles?
Form spindles in cell division, controlling movement of chromosomes.
What are the functions of lysosomes?
Contain digestive enzymes to digest material outside cells, hydrolysis of material ingested by phagocytes, breakdown of dead cells,
What is the ER?
Network of membranes enclosing fluid filled cavities (cisternae). Spread throughout cytoplasm
What is the RER?
Intracellular transport system with many ribosomes. Large SA for protein synthesis. Vesicles travel to the Golgi apparatus
What is the SER?
No ribosomes and is more tubular. Synthesises, stores and transports lipids and carbs. Contains many enzymes
What is the Golgi apparatus?
Fluid filled, membrane bound, flattened sacs. Receives vesicles from the ER containing proteins, lipids etc, before modifying and repackaging them
What is the function of the Golgi apparatus?
- In the cisternae, proteins are modified by the addition of lipids, sugars or polypeptides
- Sort, package and transport around the cell by forming vesicles
What do plant cells contain that animal cells do not?
Chloroplasts, cell wall, vacuole
What is the structure of chloroplasts?
A double plasma membrane surrounds it. The grana are flattened disks (made up thylakoids) Contains chlorophyll
What is the vacuole made up of?
Fluid filled sac with dissolved solutes, surrounded by single membrane
What is the function of the vacuole?
Maintain structure by making it turgid
Contain sugars and amino acids as temporary energy store
May contain pigments to attract pollinators
What is the cell wall made up of?
Cellulose, forming bundles of cellulose fibres
What are the functions of the cell wall?
Mechanical strength
Supports the plant
Allow for water passage between cells
Maintain cell shape
What is a fungal cell wall made up of?
Chitin
