Cell Structure Flashcards
What is a nucleus
Large organelle surrounded by a nuclear envelope which contains pores. The nucleus contains chromatin.
What is the nucleolus
Synthesised ribosomes and ribosomal RNA
What is a lysosome
A round organelle surrouned by a membrane with no clear internal structure. Contains digestive enzymes
What is ribosomes
Small organelle that floats free in the cytoplasm or is attached to the rough endoplasmic reticulum. Made up of proteins and RNA. No membrane. Protein synthesis.
What is rough endoplasmic reticulum
A system of membrane bound flattened sacs. The surface is covered with ribosomes. Protein enter the rer and are folded and processed. Transported to the golgi apparatus in vesicles.
What is the soft endoplasmic reticulum
A system of membrane bound flattened sacs but no ribosomes. Lipid synthesis
What is golgi
A group of fluid filled membrane bound flattened sacs. Formed by fusion of vesicles from the endoplasmic reticulum. Proteins from RER fuse to form flattened sacs of the golgi and the golgi further processes. Proteins enter more vesicle (lysosome) and contain digestive enzymes.
What is mitochondria
Has a double membrane- inner is folded to form a structure called cristae. Inside has matrix which contains enzymes. Inner membrane and cristae have proteins embedded that are involved in the regeneration of ATP during aerobic respiration.
What are Centrioles
Small Hallow cylinders made of microtubules that produce spindle fibres during cell division
What is chitin
Component of cell walls in fungi
What is cellulose
Component of cell walls in plants
What is in the inner membrane of the chloroplast
Have a thylakoid membrane. The flatten discs are thylakoids. Stacks are called grana
Organelles in prokaryotes
Capsule- prevent dedication, protects cells from antibiotics.
Ribosomes- smaller than eukaryotic
DNA- in a single circular loop no associated with proteins
Plasmid- small loops of DNA which can be shared between cells usually contain useful genes
Cell wall- made of murien- polysaccharide and peptide mix
Flagellum- used for locomotion
Membrane infold- increasedsurface area for respiration or photosynthesis.
Binary fission of prokaryotes
- DNA and plasmids replicate. Plasmids can be replicated many times.
- Cell elongates and DNA moves to opposite poles of cell.
- Cytoplasm begins to divide and new cell walls begin to form.
- The cytoplasm divides to produce to daughter cells. Each contain an identical DNA loop but can contain a different number of plasmid copies.
What are fungi
They are eukaryotic- they are similar to plant cells except they contain no chloroplasts and their cell walls are made of chitin not cellulose.
What is a virus
. Viruses are neither prokaryotic nor eukaryotic
. They are acellular non-living particles
. They are 1000x smaller than bacteria
. They consist of a genetic material that are protected by a protein coat called the capsid. Enclosed in a lipid envelope.
What is virus replication
- Virus detects host cell by recognising protein marker on its membrane. Virus attaches to cell using attachment proteins
- Virus injects genetic material into cell
- Cell reproduces the genetic material and reads it creating new viral proteins
- Virus leave cell using some of the cells own membrane to form itself
Transmission electron mircoscope
. It works by shooting a beam of electrons at a thin slice of a sample and detecting those electrons that make it through to the other side
. The TEM lets us look in very high resolution at a thin section of a sample
. This makes it particularly good for learning but how components inside a cell are structured internally
Scanning electron microscope
. Uses a focused beam of high-energy electrons which reflect off the surface of structures
. Gives a 3D image, samples do not have to be thin/cross sections
Equation to work out magnification
Image size= actual size x magnification
TEM
. shooting beams of electrons at a thin slice of a sample and etectjng those electrons that make it through to the other side.
. The TEM let us look in very high resolution at a thin section of a sample.
. This makes it particularly good for learning about how components inside a cell.
SEM
. Uses a focused beam of high-energy electrons which reflect off the surface of structures
. Gives a 3D image, sample do not have to be thin/cross sections
3 stages of ultracentrifugation
. Homogenisation
. Filtration
. Ultracentrifugation
What solution must the tissue be in
Cold isotonic buffered solution
