Cell Structure Flashcards
What is the structure of the cell surface membrane?
- 7nm
- phospholipid bilayer
- partially permeable
What are the functions of the cell surface membrane?
- control exchange of material
- protect cell organelles
What is the structure of the nucleus?
- double membrane
- 5 - 10 μm
- nuclear envelope
- nuclear pores
- nucleolus
- DNA
- chromatin/chromosomes
What are the functions of the nucleus?
- DNA replication
- RNA replication
- nuclear division
- exchange of mRNA, ribosomes, proteins through nuclear pores
What is the structure of the rough endoplasmic reticulum?
- single membrane
- continuous with nuclear envelope
- covered in ribosomes
- cisternae
What are the functions of the rough endoplasmic reticulum?
- protein modification/transport
- break off and form golgi body
What is the structure of the smooth endoplasmic reticulum?
- single membrane
- smooth surface
- cisternae
What are the functions of the smooth endoplasmic reticulum?
- lipid/steroid/hormone synthesis
What is the structure of the golgi apparatus?
- cisternae
- golgi body
- golgi vesicles
- single membrane
What are the functions of the golgi apparatus?
- packing/modifying/organising proteins
- synthesis of glycoproteins/glycolipids
- secretion of materials out of cell
- exocytosis
- makes lysosomes
What is the structure of the mitochondria?
- double membrane
- 1 μm
- inner membrane folded into cristae
- intermembrane space
- outer membrane contains porins
- matrix
- proteins/ATP/ADP on cristae and in matrix
- circular DNA
- 70s ribosomes
What are the functions of the mitochondria?
- carry out aerobic respiration by:
- link reaction, kreb’s cycle, ETC
- self-replicating
What is the structure of the ribosomes?
- 20 nm
- no membrane
- rRNA
- protein
- two subunits
What are the functions of the ribosomes?
- protein synthesis
What is the structure of the lysosomes?
- single membrane
- 0.5 μm
- filled with hydrolytic enzymes
What are the functions of the lysosomes?
- digestion of old cells
- digestion of old organelles
- digestion of bacteria
- sent outside cell
What is the structure of the microtubules?
- alpha/beta tubulin
- 25 nm
- dimers form protofilaments
- 13 protofilaments join
- arranged throughout cell to form cytoskeleton
- no membrane
What are the functions of the microtubules?
- provides structure and support
- intracellular transport
- contract and relax
- endocytosis
- spindle fibres during nuclear division
What is the structure of the centrioles?
- 9 triplets of microtubules
- arranged in a cylinder
- right angles to each other
- form centrosome region
What are the functions of the centrioles?
- move to opposite poles during mitosis
- spindle fibres protrude from centrioles
- MTOCs for formation of microtubules
What is the structure of the chloroplasts?
- double membrane
- 3 - 10 μm
- chlorophyll
- thylakoid membranes throughout
- grana (stacked discs)
- 70s ribosomes
- circular DNA
- stroma
- starch grains
What are the functions of the chloroplasts?
- photosynthesis
- chlorophyll absorbs light energy
- make ATP
- self-replicating
- food store
What is the structure of the cell wall?
- freely permeable
- cellulose fibres
- tensile strength
- lignin
What are the functions of the cell wall
- maintains pressure gradient
- gives support to cell
- gives shape to cell
What is the structure of the plasmodesmata?
- fine strands of cytoplasm
- pass through pores in cell wall
What is the structure of the vacuole?
- central
- filled with fluid (enzymes, pigments, sugars)
- tonoplast
What are the functions of the vacuole?
- acts as lysosome
- regulate osmotic properties
- tonoplast controls exchange
What are the functions of the cytoplasm?
- contains cell contents
What is the structure of the nucleolus?
- DNA from several chromosomes
- rRNA
- proteins
- no membrane
What is the structure of the cytoplasm?
- aqueous substance
- jelly or fluid-like
What are the functions of the nucleolus?
- ribosome synthesis
What are the functions of plasmodesmata?
- links cells
- allows exchange/transport
Where is ATP made?
in the mitochondria and chloroplasts
What is the function of ATP?
to provide energy to cells as the universal energy carrier
What are the features of prokaryotic cells?
- unicellular
- 1 - 5 μm
- no nucleus
- cell surface membrane
- DNA free in cytoplasm
- naked circular DNA
- 70s ribosomes
- peptidoglycan cell wall
- capsule
- pili
- flagella
- plasmid
What are the differences between prokaryotic and eukaryotic cells?
- no nucleus/nucleus
- binary fission/mitosis
- circular/linear DNA
- naked/associated DNA
- 70s/80s ribosomes
- peptidoglycan/cellulose
What are the similarities between prokaryotic and eukaryotic cells?
- cell surface membrane
- both replicate DNA and synthesise proteins
- 70s ribosomes in mitochondria and chloroplast
What are the features of viruses?
- non-cellular
- non-living
- parasitic
- single strand of RNA/DNA
- capsid
- capsomeres
