Cells Flashcards
(29 cards)
What is the nuclear envelope?
A double membrane
What are nuclear pores?
They are pores in the nuclear envelope that allow substances to move between the nucleus and the cytoplasm
What is the nucleoplasm?
It is granular, jelly-like material
What are chromosomes?
They are protein-bound linear DNA
What is the nucleolus?
A small sphere inside the nucleus which is the site of rRNA production and makes ribosomes
What is the function of the nucleus?
- Site of DNA replication and transcription (making mRNA)
- Contains the genetic material for each cell
What are the two types of endoplasmic reticulum?
1) Rough endoplasmic reticulum (RER)
2) Smooth endoplasmic reticulum (SER)
What is the structure of the rough endoplasmic reticulum (RER) and smooth endoplasmic reticulum (SER)?
What is the difference between the RER and SER structurally?
Both have folded membranes called cisternae
The rough endoplasmic reticulum RER has ribosomes on the cisternae
What is the function of the rough endoplasmic reticulum (RER)?
Protein synthesis
What is the function of the smooth endoplasmic reticulum (SER)?
To make and store lipids + carbohydrates
What is the structure of the Golgi apparatus?
- Folded membranes making cisternae
- Vesicles pinch off from cisternae
What are the functions of the Golgi apparatus?
1) Add carbohydrates to proteins to form glycoproteins
2) Produce enzymes
3) Transport, modify and store lipids
4) Form lysosomes
How are molecules transported by the Golgi apparatus?
1) Molecules are labelled with their destination
2) Finished products are transported to the cell surface in Golgi vesicles where they fuse with the membrane and the contents are released
What is the structure of lysosomes?
A bag of enzymes - contains 50 different enzymes
What is the function of lysosomes?
- Break down dead cells (autolysis)
- Release enzymes outside of cell to destroy material (exocytosis)
- Digest worn out organelles to re-use material
- Hydrolyse phagocytic cells
What is the structure of mitochondria?
- Double membrane
- Inner membrane called cristae
- Fluid centre called the matrix
- Loop of mitochondria DNA
What is the function of mitochondria?
- Site of aerobic respiration
- Site of ATP production
- DNA to code for enzymes needed in respiration
What is the structure of ribosomes?
Small, made up of two sub-units of protein and rRNA
What are the two types of ribosomes and which cells have them?
80s ~larger ribosomes found in Eukaryotic cells
70s ~smaller ribosomes found in Prokaryotic cells
What is the function of ribosomes?
The site of protein synthesis
What is the structure of a vacuole?
Fluid-filled surrounded (FFS ) by a single membrane called a tonoplast
What is the function of a vacuole?
- Make cells turgid, so provides support
- Temporary store of sugars + amino acids
- Pigments colour petals to attracts pollinators
What is the structure of a chloroplast?
- Surrounded by a double membrane
- Contains thylakoids
- Fluid filled stroma contains enzymes for photosynthesis
What is the function of chloroplasts?
The site of photosynthesis
