Eukaryotic Cells Flashcards
What is the structure of the nucleus?
Contains hereditary material
Nuclear envelope: double membrane, outer membrane is continuous with the ER, controls the entry and exit of material
Nuclear pores: allows the passage of large molecules out of the cell
Nucleoplasm
Chromosomes: protein bound DNA
Nucleolus: makes ribosomal RNA, assembles ribosomes
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What is the structure of Mitochondria?
Double membrane which controls the entry and exit of material
Cristae: extensions of the inner membrane, large surface area for respiration
Matrix: contains all the substances needed for respiration
Creates ATP
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What are chloroplasts?
The organelle which carries out photosynthesis
What is the structure of chloroplasts?
Chloroplast envelope: double membrane, controls the entry and exit of material
Grana: stacks of thylakoids
Thylakoids: contains chlorophyll, some have extensions between adjacent grana
Stroma: fluid filled matrix, possesses all the enzymes needed for photosynthesis
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How are chloroplasts adapted for photosynthesis?
Granal membranes provide a large surface area
Fluid possesses all the enzymes needed for sugar production
Contain both DNA and ribosomes to manufacture the proteins needed for photosynthesis
What is the Golgi apparatus?
Flattened sacs or cisternae Vesicles bring material from the ER Processes and packages material Produces secretory enzymes Transports, modifies and stores lipids Forms lysosomes See card
What are ribosomes?
Two subunits
Contains RNA and protein
Site of protein synthesis
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What is the difference between ribosomes in eukaryotic and prokaryotic cells?
80S: eukaryotic
70S: prokaryotic, found in mitochondria and chloroplasts
What is the smooth endoplasmic reticulum?
Lacks ribosomes
Synthesises, stores and transports lipids and carbohydrates
What is rough endoplasmic reticulum?
Has ribosomes present on the outer surface of the membrane
Large surface area for the synthesis of proteins
What are lysosomes?
Hydrolyses material ingested by phagocytes
Exocytosis to destroy material
Digests worn out organelles
Autolysis
Contains lysozymes which hydrolyse cell walls
What is the cell wall?
Found in all plant cells
Consists of microfibrils of cellulose
Middle lamella marks the boundary between cell walls
Stops the cell bursting under osmotic pressure
Strengthens the plant cell
Allows the movement of water
What is a cell vacuole?
Fluid filled sac
Single membrane called a tonoplast
Contains pigments to attract pollinating insects
Temporary food store
What is a tissue?
A group of similar cells that perform a specific function
What is epithelial tissue?
It consists of sheets of cells
It lines the surface of organs
Most have a protectors or secretory function
