Cell Ultrastructure Flashcards
What are the 3 types of cell?
- Animal (eukaryotic)
- Plant (eukaryotic)
- Prokaryotic
What is the function of the nucleus?
The nucleus contains chromatin (genetic material)
What is the nucleolus and where is it located?
- Produces ribosomes
- Within the nucleus
What is the nuclear envelope?
- Double membrane that surrounds the nucleus
- Has nuclear pores to allow molecules in and out
What is the smooth endoplasmic reticulum?
- Network of membranes, enclosing flattened sacs cisternae)
- for lipid/carbohydrate synthesis/storage
What is the rough endoplasmic reticulum?
- Network of cisternae, studded with ribosomes
- Protein synthesis/transport
What is the golgi apparatus?
- Modifies and packages proteins (into vesicles)
What are ribosomes?
- Protein synthesis
- No membrane
What are mitochondria?
- Site of aerobic respiration to release energy as ATP
- Have a double membrane
- Inner membrane folds to form cristae and has a fluid interior (matrix)
What are lysosomes?
- Vesicles that contain hydrolytic enzymes
- Breaks down waste material in cell
What are chloroplasts?
- Site of photosynthesis
- Have a double membrane
What is the cell surface/plasma membrane?
- Layer that keeps everything inside the cell
- Has small pores to allow movement of substances in and out
What are centrioles?
- Made of microtubules (component of cytoskeleton)
- 2 make up the centrosome, which helps assemble and organise spindle fibres in cell division
What is the cell wall?
- Strong so everything inside the cell is protected
What is the difference between plant and prokaryotic cells walls?
- Plant - made from cellulose
- Prokaryotic - made from peptidoglycan
What is the cytoskeleton made of?
- Microtubules
- Intermediate filaments
- Actin filaments
Function of microtubules?
- Maintains cell shape by resisting compression (push)
- Moves cells via flagella/cilia
- Moves chromosomes in cell division
- Moves organelles
Function of intermediate filaments?
- Maintains cell shape by resisting tension (pull)
- Anchors the organelles in place
Function of actin filaments?
- Maintains cell shape by resisting tension (pull)
- Moves cells via muscle contraction/ crawling (runs under surface membrane so is moving it)
- Divides cell in two during cell division (animal cells)
What is the vacuole?
- Stores nutrients the cell needs to survive
What is the membrane surrounding the vacuole?
Tonoplast
What is the cytoplasm?
The fluid that fills a cell. It contains dissolved molecules that are then used in other processes
How are proteins synthesised?
- Produced from the ribosomes on the RER
- These proteins are passed into the RER cisternae, where they are packaged into secretory vesicles
- The vesicles move along cytoskeleton to the golgi body
- Vesicles fuse with the cis face of the golgi body, where they are modified and then they leave by the trans face
- Secretory vesicles move to edge of cell, where they fuse with the plasma membrane and then contents are released from cell by exocytosis
