Foundations in Biology Module 2.4 Eukaryotic cell structure Flashcards
Define a cell
the basic unit of all living things
What are the 2 types of cells
- Eukaryotic cell
- Prokaryotic cell
What is a prokaryotic cell
Single-celled organisms which contain a simple structure
Example of prokaryotic cell
Bacteria
What is a eukaryotic cell
Multicellular organisms which have a complicated internal structure
Contain membrane-bound organelles
Examples of eukaryotic cells
Animal, plant and fungi
Define metabolism
All the chemical reactions that take place in an organism
What is the role of the rough endoplasmic reticulum (RER)
Has ribosomes bound to the surface
- Is responsible for the synthesise and transport of proteins
What is the role of the mitochondria
The site of the final stage of cellular respiration, where energy is released in the form of ATP.
Consists of a double membrane
What are the 4 main features of the mitochondria
- outer membrane
- inner membrane (highly folded)
- cristae (folds)
- matrix(fluid)
What does the inner membrane of mitochondria contain
Enzymes that are used in aerobic respiration
What is the name of DNA found in the mitochondria
Mitochondrial DNA
What is the role of the nucleolus
Area within the nucleus which is responsible for producing ribosomes
- It is composed of proteins and RNA
In the nucleolus, what is RNA used for
To make ribosomal RNA(rRNA)
When is the nucleolus visible
When cells are preparing to divide
What is the role of the cytoplasm
- Where chemical reactions take place
- Contains cytoskeleton
What is the cytoskeleton and what is it’s role in the cell
A network of fibres necessary for shape and stability of the cell
- It controls cell movement and the movement of organelles within cells.
What 4 things does the cytoskeleton consist of
- Microfilaments
- Microtubules
- Intermediate fibres
- Centrioles
What are microfilaments
contractible fibres formed from the protein actin
What is the role of microfilaments
- They are responsible for cell movement and cell contraction during cytokinesis
What are microtubules and what is their role
Globular tubulin proteins polymerise to form tubes which are used to form a scaffold-like structure that determines the shape of the cell.
They act as tracks for movement of organelles including vesicles
What are spindle fibres composed of
Microtubules
What is the role of intermediate fibres
they give mechanical strength to cells and help maintain their integrity
What is the role of the cell-surface membrane
It is selectively permeable
- It controls the movement of substances into and out of the cell and organelles
- controls which substances enter and exit cells
What are vesicles and what is their role in the cell
Sacs that have storage and transport roles
- transport materials inside the cell
What do lysosomes contain
Hydrolytic enzymes
What is the role of lysosomes
The breaking down of waste material in the cell, including old organelles
In the immune system why are lysosomes important
They break down pathogens ingested by phagocytic cells
What organelle is involved in programmed cell death/apoptosis
lysosomes
What are centrioles composed of
microtubules
What are the roles of the centrioles
- 2 associated centrioles form the centrosome which assemble and organise spindle fibres in cell division
- Organisms with cilia and flagella - centrioles position them
What is the role of the golgi apparatus
It is formed by cisternae
- It modifies proteins and lipids and packages them into vesicles
What is the role of the nucleus
- Contains coded genetic information in the form of DNA molecules
- DNA directs the synthesis of all proteins required in the cell
- DNA controls the metabolic activities of the cell
Where is DNA found in the nucleus
Nuclear envelope is a double-membrane that protects DNA from damage in the cytoplasm
What does the nuclear envelope contain that enables molecules to move into and out of the nucleus
Nuclear pores
How is chromatin formed
DNA associates with histones (protein)
How are chromosomes formed
Chromatin coils and condenses
What is the role of the smooth endoplasmic reticulum(SER)
The site of lipid and carbohydrate synthesis and storage
What is the role of ribosomes
The site of protein synthesis
What are ribosomes constructed by
RNA molecules which are made in the nucleolus
What 2 organelles contain their own ribosomes
Mitochondria and chloroplast
What is the process of protein production
- Proteins synthesised on the ribosomes on the RER. Passed into it’s cisternae and packaged into vesicles.
- Vesicles containing proteins move towards the golgi appparatus
- Vesicles fuse with the golgi apparatus. Proteins are modified and repackaged into vesicles
- Vesicles(secretory) fuse with the cell-surface membrane releasing contents via exocytosis
What is the role of the flagella(whip-like)
Enables cells mobility
How can the flagella act as a sensory organelle
It can detect chemical changes in a cells environment
What are the 2 types of cilia(hair-like)
Stationary cilia
Mobile cilia
Where can stationary cilia be found
The surface of cells
Where are stationary cilia important
Sensory organs e.g. the nose
What is the role of mobile cilia
It beats in a rhythmic manner, creating a current, causing fluids/objects adjacent to the cell to move e.g. in the trachea to move mucus away from the lungs
What is the 9+2 arrangement of a cilium( singular of Cilia)
- 2 central microtubules
- 9 microtubules surrounding the 2 central microtubules
What causes the cilia to move in a beating motion
The pairs of parallel microtubules sliding over each other
