Cell structure Flashcards
Name 5 organelles that are found in both eukaryotes.
Nucleus, Mitochondria, Ribosomes, Smooth endoplasmic reticulum (SER), Rough endoplasmic reticulum (RER).
Name 3 organelles that can be found in a plant cell but not in an animal cell.
Chloroplasts, Vacuole, Cell wall
Name an organelle that can be found in an animal cell but not in a plant cell.
Centriole
What is the function of a nucleus?
Controls and regulates the activities of the cell (growth and metabolism) and carries the genes, structures that contain the hereditary information.
What is the function of a smooth endoplasmic reticulum?
Contains enzymes that catalyse reactions involved with lipid metabolism.
Involved with absorption, synthesis and transport of lipids.
What is the function of a mitochondria?
Mitochondria is the site of ATP production during aerobic respiration.
What is the function of a rough endoplasmic reticulum?
Intracellular transport system, the cisternae form channels for transporting substances from one area of the cell to another.
They provide a large surface area for ribosomes, which assemble animo acids into proteins.
What is the function of the Golgi apparatus?
Proteins are modified and packaged into vesicles by the Golgi apparatus they are then pinched off and either stored in the cell or moved to the plasma membrane.
What is the function of the chloroplasts?
Chloroplast is the site of photosynthesis.
What is the function of a ribosome?
Bound to the RER mainly for synthesising proteins that will be exported outside the cell.
The singular ribosomes that are free in the cytoplasm are the site of assembly of proteins that will be used within the cell.
What is the function of centrioles?
Before a cell divides, the spindle, made of threads of tubulin forms from centrioles.
Centrioles are involved in the formation of undulipodia and cilia.
What is the function of the cytoskeleton?
- Protein microfilaments within the cytoplasm give support and mechanical strength, keeps the cells shape and allows cell movement.
- Microtubules also provide shape and support to cells and help substances and organelles to be transported through the cytoplasm within a cell; they form the track along which motor proteins walk and drag organelles from one part of a cell to another, they also form spindles before a cell divides. these enable chromosomes to move within the cell. also make up cilia and undulipodia.
- intermediate filaments are made up of a variety of proteins they anchor the nucleus within the cytoplasm and extend between cells in some tissues, between special junctions, enabling cell-cell signalling and allowing stability of tissues
What is the function of the cellulose cell wall?
They provide strength and support, maintaining the cells shape, they are permeable and allow solutions to pass through.
Name the proteins that make up the cytoskeleton.
Actin filaments, microtubules, and intermediate filaments, microfilaments and cytoskeleton motor proteins.
Describe the structure of the cellulose cell wall
Cellulose is made up of many beta glucose molecules. when 60 to 70 cellulose chains are bound together in a way, they form microfibrils which are 10 to 30nm in diameter. these then bundle together into microfibrils containing 400 microfibrils which are embedded in pectins to form plant cell wall.
Name the organelles that are involved in secreting protein.
Nucleus, RER, ribosomes, transport vesicles, Golgi apparatus, Golgi vesicles, cell membrane.
State similarities between a prokaryotic cell and a eukaryotic cell.
They are similar as they contain some of the same components as eukaryotes such as a plasma membrane, cytoplasm, ribosomes and DNA and RNA.
Name 4 stains and their uses.
Methylene blue - all purposes
Acetic orcein - binds to DNA and stains chromosomes dark red.
Eosin - stains cytoplasm
Sudan Red - stains lipids
Iodine in potassium solution - stains the cellulose in plant cell walls yellow and starch granules blue/black.
Magnification calculation
Magnification = (Image size) / (Actual size of specimen)
Describe the process of secreting protein.
- The gene that has the coded instruction for a protein is transcribed into a length of RNA called messenger RNA.
- Many copies of the mRNA are made and they pass out of the pores in the nuclear envelope to the ribosomes.
- at the ribosomes, the instructions are translated and the protein molecule is assembled.
- The protein molecule pass into the cisternae of the RER and along these hallow sacs.
5.
Describe the process of making and secreting protein.
- mRNA copy of a protein is transcribed.
- mRNA passes through nuclear pores into the cytoplasm.
- mRNA attaches to a ribosome on the RER and the protein is synthesised.
- The protein is placed into a transport vesicle which travels towards the Golgi apparatus
- The transport vesicles fuse with the Golgi apparatus.
- The protein is processed and packaged by the Golgi apparatus.
- Golgi vesicles move towards and fuse with the plasma membrane on the cell surface.
- The protein is then secreted from the cell by exocytosis.
What is the structure of the nucleus?
The nucleus is surrounded by a double membrane called the nuclear envelope.
the nucleolus does not have a membrane around it, it contains RNA.
chromatin is the genetic material, consisting of DNA wound around histone proteins.
What is the structure of the mitochondria?
They may be spherical, rod-shaped or branched and are 2-5 um long.
They are surrounded by two membranes with a fluid filled space between them. The inner membrane is folded into cristae.
The inner part is a fluid filled matrix
What is the structure of the SER?
A system of membranes that contain fluid filled cavities that are continuous within the nuclear membrane.
