Biology AS OCR Unit 1

Unit 1, Module 1 Of Biology AS OCR
  
Created Jan 10, 2010
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What type of organisms are made up of prokaryotic cells?
Bacteria
Why type of organisms are made up of eukaryotic cells?
Everything but bacteria
Where does ATP take place in prokaryotes?
In invaginations of the cell membrane called mesosomes.
What is a membrane feature of prokaryotes?
They have only the cell surface membrane and therefore do not contain membrane bound organelles...
What can be found in a prokaryotic cell which is not found in a eukaryotic cell?
Plasmids - very small loops of DNAand a nucleoid - DNA NOT surrounded by a membrane
What is the cell wall of a prokaryote made of?And what is the average size of a prokaryote?
Peptidoglycan1-5um
What is the cell membrane of a prokaryote made of?
Phospholipid Bilayer.
What is the size of a eukaryote nucleus?
10-20nm
Name the shell of the nucleus and its function
Nucleur envelope, to seperate DNA from cell content.
What does the outer membrane of the nuclear envelope join with?
Rough Endoplasmic Reticulum
What does the nucleolus contain?
Chromatin, dark staining area of nucleus.DNA coding for rRNA (ribosomal RNA)
Two features and one function of ribosome
Made of rRNA and protein and attached to Rough ER or found free.Protein synthesisPA...
Two features and one function of Rough ER
Consists of flattened membrane bound sacs called cisternae and studded with ribosome.Transports...
Two features and one function of Smooth ER
Consists of flattened membrane bound sacs called cisternae and have no ribosomes.Synthesis...
Describe the stages of function of the Golgi Body
Proteins + Lipids move through Golgi body via vesicles budding off one compartment and fusing...
Features and purpose of lysosomes
Vesicles containing hydrolytic enzymes + spherical sacs surrounded by 1 membraneBreak away...
Two features and function of MitochondriaDraw and label a diagram
Two membranes seperated by a liquid filled space.Inner membrane highly folded to form cristae...
Features and function of cytoskeleton
Network of fibres made of protein, keep cell's shape stable -> providing an internal framework.i.e...
Features and function of Undulipodia (flagella) and cillia
Structurally the same, each composed of a cyinder that contains nine doublet-microtubules...
Features and function of centrioles
Made up of nine triples of microtubules + occur in pairs at right anglesOrganise spindle during...
Cell Wall features and function
Cellulose fibres in strong structure, fully permeable Give cell mechanical strength +...
Vacuole features and function
Sac which fills with water and solutes.Pushes against cell wall to give support.P
Chloroplast features and function
Two membranes with fluid filled space.Contain flattened membrane sacs - ThylakoidsStack of...
Ribosome type in Prokaryotic and Eukaryotic cell?
70S for Prokaryotic and 80S for Eukaryotic
What are the steps to protein synthesis?
-DNA copied to mRNA-mRNA leaves through nuclear pore and attatched to ribosome (on RER)-Ribosome...
How permeable is the phospholipid bilayer? 
Partially Permeable
What are the features of the head?
Phosphate head -> hydrophillic (likes water)
What are the features of the tail?
TWO fatty acid tails -> hydrophobic (dislikes water)
What charge does a phosphate head have?
Negative charge.
What are at least 2 function of a phospholipid bilayer? And state its average size
Act as a barrierSeperate cell organelles from cytoplasmCell recognition and signallingControl...
What is an intrinsic protein?
Protein goes through the bilayer
What is an extrinsic protein?
Protein on the outside of the bilayer
What is the use of cholesterol?
Strengthen PL bilayer and decrease permeability
What is a glycolipid?
Carbohydrates attatched to phospholipid head
What is a glycoprotein?
Carbohydrate attached to protein
What is the use of glyco-proteins/lipids?
Act as chemical/hormone receptors 
What can pass through the cell surface membrane?
Water and SOME solutes.Aquaporins allow for up to 1000 times for permeability to water.
Why is it sometimes said to be a fluid-mosaic model?
Fluid - Phospholipid bilayer can move from side to side freely in plasma membraneMosaic - Due...
If a hormone fits in a receptor it is said to be..?
Complimentary
What is cell signalling?
Cells communicating with each other via signals (hormones)
Why might a cell signal?
To communicate.Growth, development, movement.React to external and internal issues.
Define magnification 
The degree to which the size of an image is larger than the object itself
Define resolution
The degree to which it is possible to distinguish between two objects very close together.
What resolution and magnification can be reached by a light microscope?
x1500 magnification200nm resolution
What resolution and magnification can be reached by a SEM
(High detail 3D)x100,000 magnification0.1/0.2 nm res
What resolution and magnification can be reached by a TEM?
HD 2Dx500,000 mag0.1/0.2 nm res
What is the equation for magnification and how many um in 1mm
magnification = image/actualactual = image/magnification1000um in 1mm
Why must a sample be stained?
Light Microscope - Chemicals added to see detailTEM/SEM - Lead salts to scatter electrons different...
Describe diffusion
The movement of molecules from an areas of high concentration of a molecules to an area of...
Describe facilitated diffusion
Large or charged molecules have to be diffused with facilitation.
How are channel proteins used with facilitated diffusion?
Form pores in membrane - shaped to allow only one type of ion through (gated - can be open...
How are carrier proteins used in facilitated diffusion?
Shaped so specific molecules can fit into them at the membrane surface. Protein changes shape...
Describe three features of Active Transport
Use metabolic energy (ATP) to change shape of proteinsCan carry against diffusion gradientMuch...
Describe features of Endocytosis
Moving large quantities of material inside cell.ATP used to form vesicles and move these around...
Describe features of Exocytosis
Moving large quantities of material out of cellATP used againBulk transportCan fuse with or...
What are the passive processes and what does this mean?
No energy required - Osmosis, Diffusion and Facilitated diffusion
What are the active processes and what does this mean?
Energy required in form of ATPActive transport and Exo/Endocytosis
What is osmosis?
Movement of water molecules only by diffusion and across a partially permeable membrane.Movement...
What is meant by the term turgid and which cells does this affect?
Plant cellWater moves in to plant cells causing expansion of vacuole, does not burst due to...
What is meant by the term haemolysed and which cells does this affect?
Animal cellsWater moves in to animal cells causing the cell to burst
What is meant by the term plasmolysed and which cells does this affect?
Plant cellsCell membrane palls away from cell wall as water leaves
What is meant by the term crenated and which cells does this affect?
Animal cellsCell shrinks and appears wrinkled as water leaves
In terms of the cell cycle how long is mitosis?
It is short, only a small percent
What stages does interphase contain?
G1, S, G2
What is G1 in the cell cycle?
Growth of the cell in size and increase in organelles
What is S in the cell cycle?
Synthesis of new DNA, chromosomes copied
What is G2 in the cell cycle?
Second growth phase
What are the four stages of mitosis?
ProphaseMetaphaseAnaphaseTelophase
What happens in Prophase?
Chromosomes shorten and thicken (supercoil to become visible as two chromatids)Nuclear Envelope...
What happens in Metaphase?
Chromosomes arranged in equator of cellAttach to spindle fibres via centromeres
What happens in Anaphase?
Centromere dividesspindle fibres pull one of each to either poleChromatids now called daughter chromosomes
What happens in Telophase?
Daughter Chromosomes reach poles of the cell.Nuclear envelope forms around each group.Lengthen...
What happens in Cytokinesis?
Whole cell splits to form two new cells.Animal cell membranes nip.Plant cells - cell plate...
How does yeast reproduce?
Undergo cytokinesis by producing a small 'bud' which nips of the cell -> this is called...
Cells which are produced as a result of meiosis are not genetically
identical
Define the term Stem Cell
Undifferentiated cells that are capable of differentiating into multiple possible cells.No...
Define differentiation
The development and changes seen in cells as they mature to form specialised cells
What are erythrocytes and what are neutrophils?
Erythrocytes are red blood cells.Neutrophils are a type of white blood cell
Where are blood cells produced?
Undifferentiated stem cells in bone marrow
How do they become erythrocytes?
Nucleus, mitochondria, golgi body and RER, lost and cell becomes biconcave.
How to they become neutrophils?
Keep nucleus, cytoplasm appears granular because of large numbers of lysosomes being produced.
How are the xylem and phloem produced?
Produced from the meristem in the cambium.
How do they become xylem cells?
Produce small cells which elongate, and become reinforced and waterproofed by lignin whilst...
How do they become phloem tissue?
Produce cells which elongate and line up end to end to form a long tube,Ends do not break down...
How are erythrocytes specialised?
Contain haemoglobin to attach to oxygen.Loss of organelles means more space .Biconcave shape...
How are neutrophils specialised?
Contain lots of lysosomes which contain hydrolitic enzymes for destroy foreign bodies.
How are sperm cells specialised?
Contain many mitochondria for ATPSperm head contains acrosome to penetrate eggVery small and...
How are squamius epithelial tissue specialised?
Very thin -> decreased diffusion distanceForm smooth flat surface ideal for lining for tubes...
How are ciliated epithelial tissues specialised?
Cell surface exposed is covered by cilia, which wave in sync to move particles i.e mucus.Cilia...
How are root hair cells specialised?
Have hair like projection from surface out ointo soil to increase surface area. Uses ATP
How are palisade cells specialised?
Large number of chlorplastsNear top of the leaf for max sun lightCylindrical shape and large...
How are guard cells speciliased?
Control opening and closing of stoma (stomata)Water moved in they become turgid spirals in...
Define the term tissue
A group of similar cells which perform the same particular function
Define the term organ
Collection of tissues which work together to perform a particular function or particular group...
Define organ system
A group of organs which work together to perform a particular task/function
How are squamous epithelial cells arranged in a tissue?
The cells are held in place by the basement membrane, which is secreted by the epithelial cells....
How are xylem and phloem arranged in leaf tissue?
CuticleUpper EpidermisPalisade mesophyll cellXylemPhloemSpongy mesophyll cellLower epidermisGuard...


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