cells Flashcards
What are the functions of lysosomes?
- hydrolyse phagocytic cells
- exocytosis - releases enzymes to the outside of the cell to destroy material
- completely break down dead cells (autolysis)
What are the functions of Golgi Apparatus?
- secrete carbohydrates
- form lysosomes
- transport, modify and store lipids
- add carbohydrates to form glycoproteins
- produce secretory enzymes
- molecules are ‘labelled’ with their destination
What are the functions of mitochondria?
- site of ATP production
- site of aerobic respiration
- has the DNA that codes for the enzymes needed for respiration
What are the functions of a nucleus?
- site of DNA replication and transcription (making mRNA)
- contains the genetic code for each cell
What are the functions of the SER?
- synthesis
- stores lipids and carbohydrates
What are the two types of electron microscopes?
- scanning electron microscope (SEM)
- transmitting electron microscope (TEM)
What is the formula for magnification?
magnification = size of image / size of object
What are the features of an SEM?
- SEMs knock electrons off the specimen and these electrons come together to form an image
- SEM images can be three-dimensional
- Specimens do NOT have to be thin like when using a TEM
- Resolution is lower than that produced by a TEM
What are the features of a TEM?
- TEMs use electromagnets to focus the electron beam
- TEMs are high resolution microscopes
- in thin specimens, you can see the internal structures of organelles such as chloroplasts
What is meant by ‘membrane-bound organelle’?
an organelle that is surrounded by a phospholipid layer
Examples of membrane bound organelles
- mitochondria
- endoplasmic reticulum (SER and RER)
- chloroplasts
- lysosomes
- nucleoli & nuclei
Examples of non-membrane bound organelles
- ribosomes
- cytoskeleton
- centrioles
What is meant by magnification?
how many times bigger the image is compared to the object
What is meant by resolution?
the minimum distance that objects can be in order for them to appear as separate things
Why is a solution cold in homogenisation?
so the the rate of enzyme (lysosyme) activity is decreased
