Biology a level flashcards spec distilled
What are the components found within the nucleus?
nuclear envelope - double membrane
nuclear pores
nucleoplasm - granular jelly-like material
chromosomes - protein-bound linear DNA
nucleolus - small sphere inside the nucleus which makes rRNA and ribosomes.
What are the functions of the nucleus?
site of DNA replication and transcription ( making mRNA)
contains the genetic code of each cell
What are the two types of endplasmic reticulum ?
- rough and smooth endoplasmic reticulum. both have folded membranes called cisternae
- rough endoplasmic reticulum has ribosomes on the surface
What is the function of the rough and smooth endoplasmic reticulum ?
RER - protein synthesis
SER - synthesises and stores lipids and carbs
What are the structures of the golgi apparatus ?
folded membranes making cisternae
secretory vesicles pinch off from the cisternae
What are the functions of the Golgi apparatus ?
- add carbohydrates to protein to form glycoproteins
- produce secretory enzymes
- secrete carbohydrates
- transport, modify and store lipids
- form lysosomes
What are lysosomes ?
bags of digestive enzymes, can contain 50 different enzymes.
What is the function of lysosomes ?
- hydrolyse phagocytic cells
- completely break down dead cells ( autolysis)
- exocytosis: releasing enzyme to outside of cell to destroy material
- digest worn-out organelles for reuse of materials
What are the components of the mitochondria?
- double membrane
- inner membrane called the cristae
- fluid centre called mitochondrial matrix
- loop of mitochondria DNA
What is the function of the mitochondria?
- site of aerobic respiration
- site of ATP production
- code for enzymes needed in respiration
What is the structure of ribosomes? include the two types.
made up of two subunits: proteins and rRNA
80s - large ribosome found in eukaryotic cells
70s - smaller ribosome found in prokaryotic cells, mitochondria and chloroplasts
What is the function of ribosomes ?
site of protein synthesis
What is the structure of a vacuole ?
filled with fluid, surrounded by a single membrane called a tonoplast
What is the function of a vacuole ?
- makes cells turgid and therefore provides support
- temporary stores of sugar and amino acids
- the pigment may colour petals to attract pollinators
What is the structure of chloroplasts ?
- surrounded by a double membrane
- contains thylakoids( folded membranes embedded with pigments such as chlorophyll and proteins).
- fluid filled stroma contains enzymes for photosynthesis
