Eukaryotic cell structure Flashcards
What is the nucleus?
Contains DNA which codes for all protein synthesis.
What is the nuclear envelope?
DNA is contained within the nuclear envelope(protect it from damage in cytoplasm).
The nuclear envelope contains nuclear pores which allows RNA and other molecules to enter and exit through
What is the nucleolus’ function+structure?
Area in the nucleus responsible for ribosome production. Made of proteins and RNA
What is a mitochondria’s function+structure?
-Mitochondria are the site of cellular respiration, energy stored in molecules bonds is broken and made into ATP.
- They have a double membrane, inner memb highly folded=cristae, fluid inside is called the matrix.
-Can produce own enzymes+replicate themselves
What are vesicles?
Membranous sacs filled with fluid used to transport materials inside the cell
What are lysosomes?
-Specialised vesicles that contain lysozyme enzymes.
-Break down waste material in cells. Play an important role in breaking down pathogens+ apoptosis
What is the cytoskeleton?
-Present in the cytoplasm of all eukaryotic cells.
-Network of fibres which provide structure+stabilty. Controls cell movement+ organelle movement
-Forms cell surface projections like flagella and villi(made of microtubules)
What are the 3 cytoskeleton components?
- Microfilaments
- Microtubules
- Intermediate fibres
What are microfilaments?
-Contractile fibres formed from the protein actin.
-Aid splitting of cytoplasm during cytokinesis, also involved in cell shape and movement
What are microtubules?
-Polymer of globular tubulin proteins, create a hollow tube(larger than microfilaments)
-Maintain cell structure
-Form spindle fibres in cell division
-Act as a track for motor proteins(actin, myosin)
What are spindle fibres?
Have a role in chromosome separation during cell division, made of microtubules
What are intermediate fibres?
Mechanical strength to cells, help anchor nucleus in cytoplasm, maintains their integrity.
What are centrioles?
-Component of cytoskeleton.
-Made of microtubules, 9+2 arrangement
-Involved in organisation of spindle fibres during cell division
-Help position flagella+cilia
What are flagella?
Whip like extensions that enable cell mobility. Sometimes used as a sensory detector
What are cilia?
-Hair like extensions which can be mobile or stationary.
-Stationary=on surface of many cells, sensory in nose.
-Mobile=beat in a rhythmic manner, creating currents causing objects adjacent to the cell to move. Eg in trachea to move mucus away from lungs
What is the SER?
Responsible for lipid and carbohydrate synthesis+storage
What is the RER?
Ribosomes bound to the surface, protein synthesis and transport
What are ribosomes?
-Free floating or attached to RER, made of RNA and are the site of protein synthesis.
-Eukaryotes=80s
-Organelles+prokaryotes=70s
What is the golgi apparatus?
Smooth structure formed of cisternae. Modifies proteins by folding them and adding other molecules. Package proteins into vesicles.
What is the cellulose cell wall(plants)?
Permeable so substances can pass through, give cell shape. Cell contents press against cell wall=rigid=structure
What are vacuoles?
Membrane(called the tonoplast in plant cells=selectively permeable) lined sacs containing cell sap
What are chloroplasts?
-Responsible for photosynthesis in plant cells.
-Have a double membrane structure
-Fluid inside=stroma
-Flattened sacs called thylakoids stack up to make a granum. These are joined by membranes called lamellae
