Biology Midterm Review Essay
Biology Midterm Review
1.1
• The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful prediction
• Scientific thinking usually begins with observation, the process of gathering information about events or processes in a careful
-observation generally involves using the senses esp. hearing & sight
-the information gathered from observations is called data.
• Quantitative date expressed as number
-Qualitative data are descriptive and involve characteristics
• After observations, the researchers will propose one or more hypotheses.
• A hypothesis- is a proposed scientific explanation for a set of observation
-some hypotheses are tested …show more content…
Electron microscopes produce magnified images by focusing beams of electrons.
-most commonly used microscope
• Compound light microscopes – allow light to pass through the specimen and use two lenses to form an image.
• Electron microscope- use beams of electrons, rather than light, to produce images.
• Transmission electron microscope (TEMs) shine a beam of electrons through a thin specimen.
• Scanning electron microscopes (SEMs) scan a narrow beam of electrons back and forth across the surface of a specimen.
2.1
•
• Most elements are found combined with other elements in compound.
• A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions.
• The main types of chemical bonds are ionic bonds and covalent bonds
• An ionic is formed when one or more electrons are transferred from one atom to another
-an atom that loses electrons has a positive charge.
-an atom that gains electrons has a negative charge
• These positively and negatively charged atoms are known as ions
• A covalent bond- forms when electrons are shared between atoms.
-when the atoms share two electrons, the bond is called a single covalent
1.1
• The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful prediction
• Scientific thinking usually begins with observation, the process of gathering information about events or processes in a careful
-observation generally involves using the senses esp. hearing & sight
-the information gathered from observations is called data.
• Quantitative date expressed as number
-Qualitative data are descriptive and involve characteristics
• After observations, the researchers will propose one or more hypotheses.
• A hypothesis- is a proposed scientific explanation for a set of observation
-some hypotheses are tested …show more content…
Electron microscopes produce magnified images by focusing beams of electrons.
-most commonly used microscope
• Compound light microscopes – allow light to pass through the specimen and use two lenses to form an image.
• Electron microscope- use beams of electrons, rather than light, to produce images.
• Transmission electron microscope (TEMs) shine a beam of electrons through a thin specimen.
• Scanning electron microscopes (SEMs) scan a narrow beam of electrons back and forth across the surface of a specimen.
2.1
•
• Most elements are found combined with other elements in compound.
• A chemical compound is a substance formed by the chemical combination of two or more elements in definite proportions.
• The main types of chemical bonds are ionic bonds and covalent bonds
• An ionic is formed when one or more electrons are transferred from one atom to another
-an atom that loses electrons has a positive charge.
-an atom that gains electrons has a negative charge
• These positively and negatively charged atoms are known as ions
• A covalent bond- forms when electrons are shared between atoms.
-when the atoms share two electrons, the bond is called a single covalent