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COMPLETE IB Biology Review questions with 100% correct answers.
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COMPLETE IB Biology Review questions with 100% correct answers.
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COMPLETE IB Biology Reviewquestions with 100% correct answers
cell theory - .......🔷ANSWERS🔶......✔✔ -All living things are composed of cells
-cells come from preexisting cells
-Cells are smallest unit of life
Challenges to cell theory: muscle fibres - .......🔷ANSWERS🔶......✔✔ -They are fused cells, so
they're long and have multiple nucleus
-challenges cells are autonomous units
Challenges to cell theory: Giant algae - .......🔷ANSWERS🔶......✔✔ -certain species may grow large
-challenges idea cells are microscopic and larger organisms are composed of many
Challenges to cell theory: aseptate fungal hyphae - .......🔷ANSWERS🔶......✔✔ -filamentous hyphae
that are not partitioned will have continues cytoplasm
-Challenges idea living structures are composed of discrete cells
Functions of life - .......🔷ANSWERS🔶......✔✔ Metabolism: living things undertake essential
chemical reactions
Reproduction: Living things produce offspring
,Sensitivity: living things are responsive to stimuli
Homeostasis: living things maintain a stable internal environment
Excretion: living things require the removal of waste products
Nutrition: living things exchange materials with their environment
Growth: living things can move and change shape or size
Acronym: MR SHENG
Metabolic functions of paramecium and chlorella - .......🔷ANSWERS🔶......✔✔ Paramecium:
Heterotrophic for nutrition, engulfs food and absorbs gases through absorption, and solids are
removed through anal pore, liquids through vacuole
Chlorella: autotrophic, contains chlorophyll for photosynthesis, all essential materials are both
absorbed and eliminated through passive absorption
Importance of surface size and volume - .......🔷ANSWERS🔶......✔✔ Volume: Rate of metabolism
Surface area: rate of exchange between cell and environment
As cell grows, volume increases faster than SA
Cells therefore can't get too big or the cell will burn more nutrients than it is taking in--cell growth
limited
Adaptations cells can make to maximize SA:Vol - .......🔷ANSWERS🔶......✔✔ -Cells may adopt
elongated or flattened shapes
,-Cells may possess cellular extensions (ex: root hairs) or fold to plasma membrane
-cells may reduce volume by including larger central vacuoles, as plant cells do
Why is an intestine cell shaped like it is? - .......🔷ANSWERS🔶......✔✔ Has microvilli to increase SA
(allows for more material absorption)
advantages and disadvantages of light and electron microscopes - .......🔷ANSWERS🔶......✔✔ Light:
Can view living specimens and natural colors, but lower magnification and lower resolutions
Electron: higher magnification and resolution, but can only view dead specimen and view is
monochrome--false color
Differences between transmission electron micrograph and a scanning electron micrograph
- .......🔷ANSWERS🔶......✔✔ Transmission electron microscopy (TEM) generate cross-sections
through a specimen (internal image)
Scanning electron microscopy (SEM) generates a surface rendering of a specimen
determining size of an image - .......🔷ANSWERS🔶......✔✔ Actual size = Image size/magnification
magnification is usually on the image
How are cells organized in multicellular organisms? - .......🔷ANSWERS🔶......✔✔ -Cells of the
same type may group together to form tissue
-different tissues interact to form organs
-organs combine to form organ systems
, Emergent properties of cells - .......🔷ANSWERS🔶......✔✔ Emergent properties are functions
present in multicellular organisms that are not present in any of the individual component cells.
Emergent properties arise from the interaction of individual cells to produce new functions in
multicellular aggregates. An example is increased antibiotic resistance seen in biofilms
cell differentiation through selective gene expression - .......🔷ANSWERS🔶......✔✔ -All cells of an
organism contain an identical genome
-They differentiate through the expression of some genes and not others in the genome
-Activation of certain genes by chemicals signals will cause a cell to develop differently from other
cells
-Differentiation causes different cell types to become more specialized and distinct as the mature
how are genes packaged in eukaryotes? - .......🔷ANSWERS🔶......✔✔ -DNA in eukaryotes is
packaged with proteins in the nucleus to form chromatin
-Active genes are loosely packaged in an expanded and accessible form called euchromatin
-inactive genes are usually tightly packaged in a more condensed form called heterochromatin
-Packaging of chromatin varies between cells according to which genes are active and inactive
Two qualities of Stem cells - .......🔷ANSWERS🔶......✔✔ -Self renewal: Stem cells are capable of
continues division
-Potency: Stem cells are capable of differentiation (are effectively unspecialized precursors)
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