3.4- Eukaryotic cell structure Flashcards
What is the nuclear membrane and its function?
Double membrane which surrounds the nucleus. Often has ribosomes on its surface.
Function: controls the entry and exit of substances into and out of the nucleus and contains the reactions taking place within it.
What is the function of nuclear pores?
Allows the passage of large molecules out of the nucleus
What is the nucleoplasm?
Granular, jelly like material that makes up the bulk of the nucleus
What are chromosomes?
Consist of protein bound linear DNA.
What is the nucleolus and its function?
A small spherical region within the nucleoplasm.
Function: Manufactures ribosomal RNA and assembles ribosomes
What are the functions of the nucleus?
- Act as the control centre of the cell through the production of mRNA and tRNA
- Retain the genetic information of the cell in the form of DNA and chromosomes
- Manufacture ribosomal RNA and ribosomes
What is the function of the double membrane in the mitochondria?
Controls the entry and exit of material. The inner of the two membranes is folded to form cristae.
What is the function of the cristae?
Provide a large surface area for the attachment of enzymes and proteins involved in respiration.
What is the function of the matrix?
Contains proteins, lipids, ribosomes and DNA that allows the mitochondria to control the production of some of its own proteins.
Many enzymes involved in respiration are found in the matrix.
What is the overall function of the mitochondria?
- Site of aerobic respiration
- Produce ATP from glucose
What is the function of chloroplasts?
Site of photosynthesis
What are the grana?
Stacks of thylakoids containing chlorophyll.
Where light absorption takes place
What is the stroma?
Fluid filled matrix where the second stage of photosynthesis takes place.
How are chloroplasts adapted for photosynthesis?
- Granal membranes provide a large surface area for the attachment of chlorophyll, electron carriers and enzymes.
- Fluid of the stroma possesses all the enzymes required in the second stage of photosynthesis
- Chloroplasts contain ribosomes and DNA so they can quickly manufacture proteins needed for photosynthesis.
What is the function of the rough endoplasmic reticulum?
- Provides a large surface area for the synthesis of proteins and glycoproteins.
- Provide a pathway for the transport of materials.
What is the function of the smooth endoplasmic reticulum?
- Synthesise, store and transport lipids
- Synthesise, store and transport carbohydrates
What are the functions of the Golgi apparatus?
- Add carbohydrate to proteins to form glycoproteins
- Produce secretory enzymes
- Secrete carbohydrates
- Transport modify and store lipids
- Form lysosomes
What are the functions of lysosomes?
- Hydrolyse material ingested by phagocytic cells
- Release enzymes to the outside of the cell in order to destroy material around the cell
- Completely breakdown cells after they have died
What is the function of lysozymes?
Hydrolyse the cell wall of bacteria
What type of ribosomes are found in eukaryotic cells?
80s-larger
What type of ribosomes are found in prokaryotic cells?
70s-smaller
What is the function of the cell wall? (plant cells only)
- Provides mechanical strength to prevent cell bursting under the pressure created by the osmotic entry of water
- To give mechanical strength to the plant as a whole
- To allow water to pass along it so contributes to the movement of water through the plant
What are the functions of vacuoles?
- Make cells turgid
- The sugars and amino acids inside may act as a temporary food store
- The pigments may colour petals to attract insects
