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jueves, 1 de noviembre de 2018

BIOLOGY: TOPIC 1
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- Understandings:
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All living things are composed of cells, the cell is the smallest unit of life, cells only arise
from pre-exisiting cells
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Organisms consisting of only one cell carry out all the functions of life in that cell:

Metabolism, Reproduction, Sensitivity, Homeostasis, Excretion, Nutrition and Growth
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Surface area to volume ration is important in the limitation of cell size
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Multicellular organisms have properties that emerge from the interaction of their
cellular components
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The activation of different instructions (genes) within a given cell by chemical signals will
cause it to differentiate 

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Differentiation is the process during development whereby newly formed cells
become more specialised and distinct from one another as they mature

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Applications:
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• Giant algae: Can be very large in size
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Paramecium:
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jueves, 1 de noviembre de 2018
• Paramecia are surrounded by small hairs called cilia which allow it to move
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(Reproduction)

• Solid wastes are removed via an anal pore
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Use of stem cells to treat Stargadt´s disease and one other name condition
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Calculation of magnification
Mag = Image size (w/ruler) divided by Actual size
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jueves, 1 de noviembre de 2018
BIOLOGY TOPIC 1
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Understandings:


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Prokaryotes have a simple cell structure without compartmentalisation






Organisms whose cell lack a nucleus
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Divided into 4 kingdoms: Protista, Fungi, Animalia,
Plantae
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Applications:

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Structure and function of organelles within exocrine gland cells of the
pancreas and within palisade mesophyll cells of the leaf



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Prokaryotes divide by binary fission


Prokaryotic features: Cytoplasm, Nucleoid, Plasmids, Ribosomes, Cell membrane,
Cell wall, Slime capsule, Flagella, Pili
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Structure of a Plant cell: Ribosomes, mitochondrion, vacuole, chloroplast, plasma
membrane, cell wall, Golgi complex, Nucleus, Nucleolus, Endoplasmic recticulum
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3 MEMBRANE STRUCTURE

Understandings:

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Phospholipids form bilayers in water due to the amphipathic properties of
phospholipid molecules



Hydrophilic head, attracted to water
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Phospholipids spontaneously arrange into a bilayer
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Membrane proteins are diverse in terms of structure, position in the
membrane and function





Embedded w/ proteins - phospholipid bilayer
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Peripheral proteins are temporarily attached by non-covalent interactions
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Cholesterol is a component of animal cell membranes


Applications:

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Cholesterol in mammalian membranes reduces membrane fluidity and
permeability to some solutes

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jueves, 1 de noviembre de 2018

BIOLOGY TOPIC 1
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(Low concentration to high concentration) Two main types:
Primary active transport, Secondary indirect active transport
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Of small molecules
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Of water molecules
Facilitated diffusion: mov
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jueves, 1 de noviembre de 2018

▪
The fluidity of membranes allows materials to be taken into cells by
endocytosis or released by exocytosis

Endocytosis: Process which larger substances enter the cell without crossing the
membrane
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Exocytosis: Process by which larger substances exit the cell without crossing the
membrane
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Vesicles move materials within cells






Materials are transported from the ER when the membrane bulges and then buds to create

a vesicle surrounding the material
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The vesicle will fuse with the cell membrane and its materials will be expelled into the
extracellular fluid

Applications:

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Structure and function of sodium-potassium pumps for active transport
and potassium channels for facilitated diffusion in axons


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Tissues or organs to be used in medical procedures must be bathed in a
solution with the same osmolarity as the cytoplasm to prevent osmosis


BIOLOGY TOPIC 1
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Understandings:


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Cells can only be formed by division of pre-existing cells




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The first cells must have arisen from non-living material






Theory known as abiogenesis
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jueves, 1 de noviembre de 2018

Applications:

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Evidence from Pasteur’s experiments that spontaneous generation of
cells and organisms does not now occur on Earth

The law of biogenesis is largely attributed to Louis Pasteur, who demonstrated that emergent
bacterial growth in nutrient broths was due to contamination by pre-existing cells

BIOLOGY TOPIC 1
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M phase:
The period of cell cycle in which the cell and contents divide to create two genetically identical
daughter cells
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These genetically identical strands are called sister chromatids and are held
together by a central region called the centromere
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Interphase is a very active phase of the cell cycle with many processes
occurring in the nucleus and cytoplasm







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Cyclins are involved in the control of the cell cycle






Cyclins are a family of regulatory proteins that control the progression of the cell

Events need to occur in Interphase to prepare the cell for division (DNA replication,
Organelle duplication, Cell growth, Transcription/Translation, Obtain nutrients, Respiration
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Cytokinesis occurs after mitosis and is different in plant and animal cells


Process of cytoplasmic division, where the cell splits into two identical daughter
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cycle
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Either acts on
DNA or the replicative machine
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Lead to the formation of cancer,
classified as carcinogens
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DNA is present as uncondensed chromatin

Cell is enlarged in preparation for division
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The nuclear membrane breaks down and the nucleus dissolves
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Chromosomes to align along the centre of the cell
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Genetically identical chromosomes, move to opposite poles of the cells
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Cytokinesis occur, splitting the cell into two

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