Cell - the smallest unit of organization that can perform all activities
required for life;
Organelle - cellular structures with specialized functions;
Cytoplasm - the contents of the cell bounded by the plasma membrane;
Plasma membrane - the boundary of every cell that acts as a selective
barrier, regulating the cell’s chemical composition.
Nucleus - the organelle of a eukaryotic cell that contains the genetic
material in the form of chromosomes.
Most cells contain three main parts: cell membrane, cytoplasm, and nucleus
Cytosol is the liquid part of the cytoplasm that contains salts, ions, proteins, enzymes, and complex
compounds.
Cytoplasmic inclusions are non-living materials like nutrients and pigments, which are not constantly in
the cell.
Linear magnification - the ratio of image length to object length measured in planes
Micrograph; - a photograph of an image under the microscope
Convert the following measurements. a. 9.2 mm = __ μm b. 5800 μm = __ cm c. 0.077 mm = __ μm d.
0.0061 mm= __ nm
Binomial nomenclature - a system of nomenclature in which each species is given a unique name that
consists of a generic and a specific term;
Classification - systematic arrangement in groups or categories according to established criteria;
Species - a group of individuals having some common characteristics or qualities.
They are classified in this order: Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
. In binomial nomenclature, every species has its own scientific name written by two words. This name is
always written by Latin letters and in italic font. The first word is capitalized while the second starts with
a small letter.
For example, dog is named as Canis familiaris, and cat is named as Felis catus. The human scientific
name is Homo sapiens.
Exponential growth - growth at an increasingly rapid rate;
Carrying capacity- the number of organisms which a region can support
without environmental degradation;
Sigmoid curve - a mathematical graph having “S”-shaped curve
primary source of energy that powers natural systems is the sun.
Plants are producers By photosynthesis, they produce glucose
Animals are consumers, herbivores-plant eating,carnivores-animal eating(predator)
Biogeochemical cycle - the flow of chemical elements and compounds between living organisms and the
environment
Carbon - a widely distributed element that forms organic compounds in combination with hydrogen,
oxygen, etc
Nitrogen - a chemical element that is a gas with no color or taste, forms most of the earth’s atmosphere
and is a part of all living things.
About 0.04% of Earth’s crust and 0.03% of the atmosphere is carbo. It is the main element of living
things; all organic compounds include carbon
Carbon is present in the atmosphere as carbon dioxide (CO2). Water also contains CO2 as it can dissolve
it. Plants and algae use CO2 to make photosynthesis and produce various organic compounds
The Earth’s atmosphere is about 78% nitrogen gas (N2),
Fixation: bacteria and cyanobacteria change atmospheric nitrogen into ammonium (NH4+).
Nitrification: nitrifying bacteria transforms soil ammonia (NH3) into nitrates (NO2-). Plants can use
nitrogen in this form
Assimilation: plants absorb nitrates from the soil into their roots and use it.
Ammonification: the waste products of living organisms decomposed by fungi and bacteria turning
nitrogen in ammonium.
Denitrification: soil nitrates converted to free atmospheric nitrogen by denitrifying bacteria.
Deforestation - the cutting down of trees;
Erosion - the wearing away of soil by different forces (water, wind, ice, living organism, temperature);
Pollution - contamination of the environment by rubbish, oil spill and so on.
Petroleum makes a thin layer on a water surface. This layer prevents gas exchange, and fish don’t get
enough oxygen. Also, petroleum covers wings of some birds, so they cannot fly
Petroleum makes a thin layer on a water surface. This layer prevents gas exchange, and fish don’t get
enough oxygen. Also, petroleum covers wings of some birds, so they cannot fly
Herbicide - chemical used to kill weeds and other unwanted plants
Insecticide - chemical substance used to kill insects
Pesticide - chemical substance used against pests
Atmosphere - a layer of gases which surrounds the Earth
Greenhouse effect - warming of the Earth atmosphere
Greenhouse gas - a gas in the atmosphere which can trap the heat escaping from Earth.
ozone layer protects organisms on the Earth from harmful ultraviolet radiation. It absorbs ultraviolet
rays from the Sun
The gradual heating of Earth’s surface, oceans, and atmosphere is caused by human activity. The main
reason for raising the atmospheric temperature and water level of the world ocean is burning of fuels
that produce carbon dioxide (CO2), methane and other greenhouse gases into the atmosphere
Digestion - breaking down food into small particles; Stomach - saclike organ which stores and digests
food
Ingestion. Ingestion occurs when the food is taken into the mouth.
Digestion. There are two types of digestion: mechanical and chemical.
Mechanical digestion is physical breaking down of food particles by teeth in the mouth, and a little in the
stomach
Chemical digestion is chemical breaking down of food molecules by enzymes. This occurs in the mouth,
stomach, and small intestine
Enzymes -They break down large food molecules into small molecules.
Bonus
