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AQA Biology 3.3 Structure of an epithelial cell
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- 1what is a eukaryotic cell?a cell with a distinct nucleus and posses membrane bound organelles
- 2what does a nucleus do?contains cells hereditary material and controls cells activities
- 3how big is the nucleus?between 10 and 20 um
- 4what 5 parts is the nucleus made up of?-nuclear envelope
-nuclear pores
-nucleoplasm
-chromatin
-nucleolus - 5what is the nuclear envelope?double membrane that surrounds the nucleus
- 6what is the nuclear envelope connected to?ER
- 7what does it do?controls entry and exit of materials and contains reactions occurring within the nucleus
- 8what do nuclear pores do?allow passage of large molecules out of the nucleus such as mRNA
- 9what is nucleoplasm?granular, jelly-like material that makes up the bulk of the nucleous
- 10what is chromatin?the DNA found within the nucleoplasm. diffused form that chromosomes take when cell isn't dividing
- 11what is a nucleolus?a small spherical body within the nucleoplasm
- 12what does the nucleolus do?makes ribosomal RNA and assembles the ribosomes
- 13what are the three functions of the nucleus?-act as control centre of cell through production of mRNA and hence protein synthesis
-retain genetic material in form of DNA or chromosomes
-make ribosomal RNA and ribosomes - 14what shape are mitochondria?rod shaped
- 15how big are mitochondria?1-10 um in length
- 16what are the three parts of a mitochondrion?double membrane, cristae and matrix
- 17what does the double membrane do?surrounds organelle. outer one controls entry and exit of material. inner is folded into cristae
- 18what are cristae?shelf like extensions of the inner membrane.
- 19what do they do?provide large surface area for attachment of enzymes involved in respiration
- 20what is the matrix?semi-rigid material that makes up remainder of mitochondrion
- 21what does the matrix contain?protein, lipids and traces of DNA
- 22what does this allow the mitochondrion to do?control the production of their own proteins
- 23what enzymes are found in the matrix?those for respiration
- 24what are mitochondria responsible for making?ATP
- 25where are high numbers of mitochondria found?Muscle and epithelial cells
- 26what is ER?endoplasmic reticulum. 3D system of sheet-like membranes in cytoplasm. attached to the nuclear membrane
- 27what does ER contain?flattened sacs called cisterane
- 28what are the two types?RER and SER
- 29What is the characteristic of RER?has ribosome's on the outer surface of membranes
- 30what is the function of RER?-provide large SA for synthesis of proteins and glycoproteins
-provide a pathway for the transport of materials, especially proteins, throughout the cell - 31what is the characteristic of SER?lacks ribosomes on its surface and is often more tubular in appearance
- 32what are the functions of SER?-synthesise, store and transport lipids
- 33what function would men a cell needs lots of ER?manufacture and store large quantities of carbs, proteins and lipids
- 34what are examples of a cells that do this?liver and secretory cells e.g. epithelial cells that line the intestines
- 35what kind of cells have Golgi apparatus, eukaryotes or prokaryotes?almost all eukaryotes
- 36describe the structure of golgi apparatusa stack of membranes that make up flattened sacs called cisternae
- 37what are the 5 functions of the golgi apparatus?-add carbs to proteins to form glycoproteins
-produce secretory enzymes e.g. in pancreas
-secrete carbs e.g. to make cell walls in plants
-transport, modify & store lipids
-form lysosomes - 38were are golgi apparatus well developed?in secretory cells like epithelial cells lining the intestines
- 39when are lysosomes formed?when the vesicles produced by golgi apparatus contain enzymes such as proteases and lipases
- 40how many enzymes can be contained in one lysosome?up to about 50
- 41what is the purpose of lysosomes doing this?they isolate potentially harmful enzymes from the rest of the cell before releasing them outside the cell or into a phagocytic vessel within the cell
- 42what are the 4 functions of lysosomes?-break down materials ingested by phagocytic cells, such as white blood cells
-release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell
-digest worn out organelles to re-use useful chemicals
-completely break down dead cells (autolysis) - 43where are lysosomes most abundant?secretory cells such as epithelial cells and phagocytic cells
- 44what are the two types of ribosome?-70S type
-80S type - 45where are 70S type found?Prokaryotic cells
- 46where are 80S type found?eukaryotic cells
- 47how many subunits does a ribosome have?2
- 48what makes these subunits different?their size
- 49what does each subunit contain?ribosomal RNA and proteins
- 50what are microvilli?tiny projections of the epithelial cell
- 51what are they for?increase SA for efficient absorption
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- AS - Level (unit 1 - 03. cells and the movement in and out of them) AS Biology Fichas sobre AQA Biology 3.3 Structure of an epithelial cell, creado por Charlotte Hewson el 29/04/2015.
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