Eukaryotes Flashcards
What are the main organelles in animal cells and their functions?
- Nucleus: Controls cell activity, contains genetic information
- Cell Membrane: Controls movement of substances in and out of the cell
- Cytoplasm: Site of chemical reactions
- Ribosomes: Protein synthesis.
- Mitochondria: Site of aerobic respiration releases energy
Why are animals and plants classified as eukaryotes?
- Their cells contain a true nucleus
- Surrounded by a cell membrane
- DNA is contained within a nucleus.
What is cell ultrastructure?
The detailed structure of cells visible only with an electron microscope
What is the structure and function of the nucleus?
- Size: 10μm in diameter
- Contains DNA
- Nucleolus- makes ribosomes
- Surrounded by a double membrane- the nuclear envelope
- Nuclear pores allow molecules like mRNA to pass between the cytoplasm and nucleus
What is the function of mitochondria?
- Size: 1-5μm
- Site of aerobic respiration using glucose
- Produces ATP for metabolic activity
- Found in high numbers in cells with high metabolic activity
What is the structure of mitochondria?
- Double membrane: Controls entry and exit of materials
- Cristae: Extensions of the inner membrane, provide a large surface area for enzymes in respiration
- Matrix: Contains proteins, lipids, 70S ribosomes, circular DNA, and respiratory enzymes
What is the function of chloroplasts?
- Size: 2-10μm in length
- Site of photosynthesis- produces organic molecules for the plant
- Double membrane surrounds it
- Grana: Stacks of thylakoids containing chlorophyll
- Stroma: Fluid-filled matrix where the second stage of photosynthesis occurs
What is the function of the endoplasmic reticulum?
RER:
- Network of tubules connected to the nuclear envelope
- Covered in ribosomes
- Synthesises and transports proteins
SER :
- Network of tubules without ribosomes
- Synthesizes and stores lipids
What is the function of the Golgi apparatus?
Modify and sort proteins
Process:
1. Proteins from the rER are packaged into transport vesicles
2. Vesicles fuse with the Golgi- proteins are modified
3. E.g. adding carbohydrates to form glycoproteins
4. Modified proteins are packed into secretory vesicles
5. Vesicles fuse with the cell membrane to release proteins via exocytosis
What is the function of cilia and centrioles?
Cilia:
- Hair-like projections that beat in rhythm
- Move substances
Centrioles:
- Pairs of cylinders arranged at right angles
- Involved in cell division
- Producing spindle fibres for chromosome movement
- Made of microtubules
What is the process of protein production in a cell?
- DNA in the nucleus codes for biological molecules
- The rER synthesizes proteins
- Proteins are transported in a vesicle to the Golgi
- Golgi modifies proteins
- Modified protein is packaged into a transport vesicle
- Vesicle fuses with the cell membrane and releases the protein via exocytosis
