B2.2 Organelles and Compartmentalisation Flashcards
What are organelles?
Structures that are separate subunits of cells and perform a specific function
Examples include the nucleus, Golgi apparatus, mitochondria, lysosomes, chloroplasts, rough endoplasmic reticulum (RER), and smooth endoplasmic reticulum (SER)
What is compartmentalisation in cells?
The use of membranes to isolate certain parts of the cell to form separate organelles. This allows reactions to occur without interference from other cellular processes.
Internal conditions (E.g. pH) can be differentiated in the cell to maintain optimum conditions for different enzymes;
What is the function of the nucleus?
Houses nearly all the cell’s genetic material and makes ribosomes
The nucleus contains chromatin, which consists of DNA and proteins. Also contains nucleolus and the nuclear envelope
What is the role of the nucleolus?
Produces RNA, which is made into ribosomes
Ribosomes move out of the nucleus to the rough endoplasmic reticulum to produce proteins.
What is the structure of the Nuclear envelope?
A dense, spherical structure which surrounds the nucleolus, and is made up of an inner and outer membrane, separated by a fluid.
It is marked with pores which allow for exchange of relatively large molecules.
What is the function of the Cell membrane?
Semi-permeable layer that controls movement in and out of the cell.
What is the function of the Golgi apparatus?
Processes and packages proteins, which are released in Golgi vesicles
The Golgi apparatus modifies proteins received from the rough endoplasmic reticulum.
How do ribosomes differ in function?
Bound ribosomes produce proteins for export; free ribosomes produce proteins used inside the cell
Bound ribosomes are attached to the rough endoplasmic reticulum.
What are lysosomes and their function?
Contain hydrolytic enzymes for the destruction of microbes engulfed by white blood cells, and old organelles
Lysosomes are not present in plant cells.
What is the advantage of compartmentalisation in cells?
Allows for optimal internal conditions, isolation of toxic substances, and flexibility in organelle positioning
Example: Phagocytic vacuoles isolate ingested materials.
What is the structure of mitochondria?
Contains an inner and outer membrane, with the inner membrane folded into cristae
This structure increases surface area for ATP production.
What is the role of vesicles in cells?
Transport and release substances produced by the cell by fusing with the cell membrane.
Vesicles can include transport vesicles, secretory vesicles, lysosomes, and peroxisomes.
What does the chloroplast do?
Responsible for photosynthesis and contains pigments such as chlorophyll. Double-membrane bound organelle.
Chloroplasts are not present in animal cells.
What is the function of clathrin?
Plays a role in the formation of vesicles in cells
Clathrin stabilizes membrane invaginations during processes like endocytosis and phagocytosis.
Fill in the blank: The _______ is responsible for producing and storing lipids, including steroids.
Smooth endoplasmic reticulum
True or False: All organelles are membrane-bound.
False
Ribosomes are considered organelles despite not being membrane-bound.
What is the role of the rough endoplasmic reticulum?
Transports proteins produced by ribosomes to the Golgi apparatus
These proteins are usually for use outside of the cell.
What are the membranes in Chloroplasts?
Outermembrane, innermembrane, thylakoid membrane.
Compartment (space) between innermembrane and thylakoid membrane is called stroma.