2.1.1 -- Cell structure [old shit] Flashcards
How are Eukaryotic cells similar to Prokaryotic cells?
Both have a
- Plasma Membrane
- Cytoplasm
- Ribosomes for assembling amino acids into proteins
- DNA and RNA
How are Eukaryotic cells different from prokaryotic? (1)
They are:
- Much Smaller
- Less well developed cytoskeleton and centrioles
- No Nucleus
- No membrane bound organelles such as mitochondria, endoplasmic reticulum, chloroplast, Golgi apparatus
- Wall made of peptidoglycan not cellulose
How are Eukaryotic cells different from prokaryotic? (2)
Also have a
- Smaller Ribosomes
- Have Naked DNA that is not wound around histone proteins but floats free in the Cytoplasam as A loops (not linear chromosomes)
Also have:
- Protective waxy capsule surrounding their cell wall
- Small loops of DNA called plasmids, as well as the main loops of DNA
- Flagella - long ship like projections that enable them to move. (Structure different from prokaryotic undulipodia)
- pili - smaller hair like projection that enable backteria to adhere to host cells or to each
What is an electron micrograph?
Photograph of an image seen using an electron microscope
What is magnification?
Number of times larger an image appears, compared with the size of an object.
What are organelles?
Small structures within cells, which have a specific function.
What is a photomicrograph
A photograph of an image seen using an optical (light) microscope.
Resolution
The clarity of an image, the higher the resolution the clearer thr image.
What are the advantages of an Optical microscope
- Relatively Cheap
- Easy to use
- Portable, can be used in a field as well as Labs.
- Can study living organisms
What are optical microscopes?
- Magnification up to x1500
- Resolution 0.2
3.
What is the difference between Light interference and light absorption?
Light interference is used to produce a clear image without staining. Where as light absorption use staining
Name the type of staining used
- Methylene is an all purpose stain
- Acetic orcein binds to DNA and stains chromosomes dark red
- Eosin stains Cytoplasm; Sudan red stains lipids
- Iodine in potassium solution stains cellulose yellow and startch granules blue/black (looks violet under the microscope)
What is a Eukaroyric cell
Cell with an ultrastructure
- Nucleus surrounded by a double membrane called the nuclear envelope
- Has an area inside the nucleus called the Nucleolous which contains RNA, Chromosomes Unwind, making of ribosomes
- Jelly like cytoplasm in which organelles are suspended
- Cytoskeleton - network of protein filaments (actin or microtubules) within the Cytoplasam that moves organelles from one place to the of her. Allows some cells to move such as amoebae. Allows contraction of muscle cells
- Plasma membrane
- Small Vesicles
- Ribosomes (organelles without a membrane)
Describe the structure of a nucleus.
- Surrounded by a double membrane called the nuclear envelope
- Nuclear envelope has pores in it
- Nucleolous (no membrane)
- Chromatin (genetic material) wound around histone protiens.
- When cell not dividing the chromatin is spread out or extended
- When dividing it condenses and coils tightly into chromosomes
What is the function of the nucleus?
- Seperates content within the nucleus from the rest of the cell
- Some points of the nuclear envelope fuse together to allow some dissolved substances to diffuse through
- Allows large substances such as mRNA or steroid hormones to LEAVE the nucleus.
- Nucleolous, site of ribosomes production
- Chromosomes contain organisms gene
Control centre of the cell, stores genome, transmit genetic info, provides instructions for protein synthesis