2620388
Description
Flashcards by Charlotte Hewson, updated more than 1 year ago
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Created by Charlotte Hewson
over 9 years ago
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| Question | Answer |
| what is a eukaryotic cell? | a cell with a distinct nucleus and posses membrane bound organelles |
| what does a nucleus do? | contains cells hereditary material and controls cells activities |
| how big is the nucleus? | between 10 and 20 um |
| what 5 parts is the nucleus made up of? | -nuclear envelope -nuclear pores -nucleoplasm -chromatin -nucleolus |
| what is the nuclear envelope? | double membrane that surrounds the nucleus |
| what is the nuclear envelope connected to? | ER |
| what does it do? | controls entry and exit of materials and contains reactions occurring within the nucleus |
| what do nuclear pores do? | allow passage of large molecules out of the nucleus such as mRNA |
| what is nucleoplasm? | granular, jelly-like material that makes up the bulk of the nucleous |
| what is chromatin? | the DNA found within the nucleoplasm. diffused form that chromosomes take when cell isn't dividing |
| what is a nucleolus? | a small spherical body within the nucleoplasm |
| what does the nucleolus do? | makes ribosomal RNA and assembles the ribosomes |
| what 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 |
| what shape are mitochondria? | rod shaped |
| how big are mitochondria? | 1-10 um in length |
| what are the three parts of a mitochondrion? | double membrane, cristae and matrix |
| what does the double membrane do? | surrounds organelle. outer one controls entry and exit of material. inner is folded into cristae |
| what are cristae? | shelf like extensions of the inner membrane. |
| what do they do? | provide large surface area for attachment of enzymes involved in respiration |
| what is the matrix? | semi-rigid material that makes up remainder of mitochondrion |
| what does the matrix contain? | protein, lipids and traces of DNA |
| what does this allow the mitochondrion to do? | control the production of their own proteins |
| what enzymes are found in the matrix? | those for respiration |
| what are mitochondria responsible for making? | ATP |
| where are high numbers of mitochondria found? | Muscle and epithelial cells |
| what is ER? | endoplasmic reticulum. 3D system of sheet-like membranes in cytoplasm. attached to the nuclear membrane |
| what does ER contain? | flattened sacs called cisterane |
| what are the two types? | RER and SER |
| What is the characteristic of RER? | has ribosome's on the outer surface of membranes |
| what 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 |
| what is the characteristic of SER? | lacks ribosomes on its surface and is often more tubular in appearance |
| what are the functions of SER? | -synthesise, store and transport lipids |
| what function would men a cell needs lots of ER? | manufacture and store large quantities of carbs, proteins and lipids |
| what are examples of a cells that do this? | liver and secretory cells e.g. epithelial cells that line the intestines |
| what kind of cells have Golgi apparatus, eukaryotes or prokaryotes? | almost all eukaryotes |
| describe the structure of golgi apparatus | a stack of membranes that make up flattened sacs called cisternae |
| what 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 |
| were are golgi apparatus well developed? | in secretory cells like epithelial cells lining the intestines |
| when are lysosomes formed? | when the vesicles produced by golgi apparatus contain enzymes such as proteases and lipases |
| how many enzymes can be contained in one lysosome? | up to about 50 |
| what 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 |
| what 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) |
| where are lysosomes most abundant? | secretory cells such as epithelial cells and phagocytic cells |
| what are the two types of ribosome? | -70S type -80S type |
| where are 70S type found? | Prokaryotic cells |
| where are 80S type found? | eukaryotic cells |
| how many subunits does a ribosome have? | 2 |
| what makes these subunits different? | their size |
| what does each subunit contain? | ribosomal RNA and proteins |
| what are microvilli? | tiny projections of the epithelial cell |
| what are they for? | increase SA for efficient absorption |
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