Cell components Flashcards
What are the components of a nucleus?
Nuclear envelope Nuclear pores Chromatin Nucleolus Nucleoplasm
What is the function of a nucleus?
Controls mRNA and tRNA production and hence protein synthesis.
Keep the genetic material of the cell in the form of DNA and chromosomes
Make ribosomes
What is the structure of a mitochondria?
They have a double membrane and the inner membrane is folded into Cristae
The inside is called the matrix
What are cristae for?
To provide a large surface area for enzymes and proteins involved in respiration to attach onto.
What does the matrix contain?
Ribosomes,lipids and DNA
What is the DNA in mitochondria used
Controlling the production of its own proteins
What are the functions of mitochondria?
Site of aerobic respiration
Synthesis of ATP
Where are mitochondria found? And what cells have an abundance of them and why?
They are found in cells that have a high level of metabolic activity and require a lot of ATP.
E.g. Muscle cells and epithelial cells
Name the 4 structures in a chloroplast?
Chloroplast envelope
The grana
Thylakoids membrane
The stroma
How are chloroplasts adapted to their function?
The grana have a large surface area for the attachment of things.
Chloroplasts contain DNA and ribosomes so they can manufacture proteins needed for photosynthesis.
What are the two types of endoplasmic reticulum?
SER AND RER
What is the rough ER for?
It contains ribosomes and a large surface area for the synthesis of proteins and glycoproteins.
Provides a pathway for the transport of proteins.
What is the smooth ER for?
It lacks ribosomes
It synthesises,stores and transports lipids
It synthesises,stores and transports carbohydrates.
What type of cells have a large ER?
Cells that manufacture a large amount of carbohydrates,proteins and lipids . eg the liver
What is the structure of the Golgi apparatus?
It’s made of flattened sacs of membranes called cisternae surrounded by vesicles
What are the functions of the Golgi apparatus?
Golgi modifies the proteins made from the ER and adds carbohydrate components to them to form glycoproteins.
It produces secretory enzymes
Transports,modifies and stores lipids.
Forms lysosomes.
What is exocytosis?
When a Golgi vesicle moves to the surface and fuses with the cell membrane releasing the content of it to the outside.
Where is the Golgi apparatus well developed?
In secretory cells like the intestines.
What are Lysosomes?
When Golgi vesicles contain enzymes that hydrolyse cell walls of bacteria. (Lysozyme)
What is the function of a lysosome?
Hydrolyzes material ingested by phagocytes
Digest worn out organelles
Break down cells after they have died.
What is the function of a ribosome?
Protein synthesis.
How much of the dry mass of a cell are ribosomes?
25%
What ribosomes are found in eukaryotes?
80S ribosomes
What is the function of a cell wall?
To provide mechanical strength to prevent the cell bursting under pressure.
What is the structure of a vacuole?
A fluid filled sac with a single membrane
What is the function of a vacuole?
Supporting plant cells by making them turgid
Act as a temporary food store
