Biology (Cells) Flashcards
The chemical constituents of organisms can be divided into?
Inorganic substances (No carbon atoms)
-Water(65%,% by weight)
-Minerals(1%)
Organic substances (Biomolecules) (Many carbon atoms)
-Carbohydrates(5%)
-Lipids(10%)
-Proteins(18%)
-Nucleic acids(1%)
What are the functions of nitrate ions in animals and plants?
Animals: //
Plants: a source of nitrogen for synthesis of proteins, a source of nitrogen for synthesis of nucleic acids for heredity
What are the functions of magnesium in animals and plants?
Animals: activates some enzymes
Plants: component of chlorophyll, activates some enzymes
What are the functions of iron in animals and plants?
Animals: a component of haemoglobin in red blood cells, activates some enzymes, a component of ATP (energy carrier) to support body activities
Plants: Activates some enzymes, a component of ATP (energy carrier) to support body activities
What are the functions of calcium in animals and plants?
Animals: A component of bone and teeth, required in blood clotting, muscle contraction, sending messages in nervous system
Plants: Helps strengthen cell walls
What are the functions of phosphate in animals and plants?
Animals: A component of bones and teeth, A component of phospholipid in cell membrane, A component of nucleic acid for heredity
Plants: A component of phospholipid in cell membrane, A component of nucleic acid for heredity
All organice chemical constituents of organisms contain what? They are also known as ____.
Carbon
Biomolecules
Name examples of proteins and their functions.
Structural proteins: Make up body tissues ( e.g. hair, nails)
Enzymes: Catalyses chemical reactions in organisms
Hormones: Regulate body processes in organisms (e.g. growth, menstruation)
Antibodies: Protect the body against diseases for immunity
Haemoglobin: Carries oxygen
Name examples of nucleic acids and their functions.
Deoxyribonucleic acid (DNA): Carries genetic information for heredity
Ribonucleic acid (RNA): Takes part in the synthesis of proteins in cells
What are all the types of microscopes?
Light microscope
Electron microscope (For dead specimen) : Transmission electron microscope (TEM), Scanning electron microscope(SEM)
What is the (1) working principle, (2) maximum magnification, (3) appearance of image produced, (4) advantages of light microscope?
(1): Light passes through a specimen/ a thin slide of specimen to form an image
(2): 1600 times ( usually 40x-400x)
(3): colored image
(4): Living specimens can be observed, easier preparation of specimen
What is the (1) working principle, (2) maximum magnification, (3) appearance of image produced, (4) advantages of transmission electron microscope?
(1): Electrons pass through a thin slide of specimen to form an image
(2): 1 500 000 times
(3): Black and white image, 2D showing the internal structures of the specimen
(4) Higher magnification and thus higher resolution of images
-> Resolution : ability to distinguish two adjacent objects as distinct from each
other
What is the (1) working principle, (2) maximum magnification, (3) appearance of image produced, (4) advantages of scanning electron microscope?
(1): Electrons scan over the surface of the specimen to form an image
(2): 200 000 times
(3): Black and white image, 3D image showing the external structures of the
specimen
(4): Higher magnification and thus higher resolution of images
-> Resolution : ability to distinguish two adjacent objects as distinct from each
other
What is the property of an image shown through a microscope?
Inverted and reversed laterally
Total magnification =?
size of object=?
Magnification of eyepiece x magnification of objective
size of image / magnification
The brightness of a low-power magnification image is ___, while a high-power one is ___.
brighter
dimmer
What is the occurance(1), and feature and function(2) of nucleus?
(1) Usually at centre for animal cell
(2) Spherical and bounded by nuclear membrane, Contains genetic material i.e. DNA, Controls activities of cell, Involved in making ribosomes, Absent in some cells ( e.g. red blood cells) for having more space to carry O2
What is the occurance(1), and feature and function(2) of cytoplasm?
(1) Confined by cell membrane
(2) Jelly-like fluid consisting of mainly water and proteins, organells , minerals, etc
Holds organells, Provides a site for chemical reactions to take place, Allows movement and transport of materials inside the cell
What is the occurance(1), and feature and function(2) of cell membrane?
(1) As boundary enclosing cytoplasm
(2) Thin and flexible membrane, Mainly made up of phospholipid and protein, Separate cell contents from outside environment, Differentially parmeable, controls movement of substance into and out of the cell
What is the occurance(1), and feature and function(2) of endoplasmic reticulum?
(1) A network of interconnected membrane-bound sacs and tubes
(2) Continuous with outer nuclear membrane and extends throughout cytoplasm,
Rough ER ( with ribosomes attached ) is involved in the synthesis of proteins
->Abundant in cells that produce a large amount of protein
Smooth ER ( no ribosome attached ) in involved in the synthesis of lipids
->Abundant in cells that produce a large amount of lipids
What is the occurance(1), and feature and function(2) of ribosomes?
(1)Attached on Rough ER or free lying in cytoplasm
(2) A small particle not surrounded by membrane, Made up of protein and ribosomal(RNA), Involved in the synthesis of proteins
What is the occurance(1), and feature and function(2) of mitochrondrion
(1) Abundant in active cells that needs a lot of energy
(2) Bounded by a double membrane, With the highly folded inner membrane, Main site of respiration to release energy
-> Abundant in liver cells, muscle cells, root hair cells, intestinal epithelial cells,
sperms, etc
->Absent in red blood cells
What is the occurance(1), and feature and function(2) of cell wall? (only in plant cells)
(1) A thick layer of covering cell membrane
(2) Thick, rigid outermost layer mainly made up of cellulose, Freely permeable, Protects, supports and gives shape to pant cell
What is the occurance(1), and feature and function(2) of chloroplast? (only in green plant cells)
(1) Present in all green plant cells
(2) Bounded by a double membrane, Contains chlorophyll, a green pigment which captures light for photosynthesis to produce food, Often contains starch, Larger than mitochondrion
