4. THE CHEMICAL BASIS OF LIFE Flashcards

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1
Q
  1. What are organisms composed of?
A
  • matter
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2
Q
  1. What is the definition of matter?
A
  • anything that takes up space and has mass
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3
Q
  1. What is matter made up of?
A
  • elements
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4
Q
  1. What is the definition of elements?
A
  • substances that cannot be broken down into other substances through chemical reactions
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5
Q
  1. How many elements exist in nature, and where are they listed?
A
  • 92 elements exist in nature
  • they are listed in the Periodic Table
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6
Q
  1. What are compounds?
A
  • a substance consisting of 2 or more elements
  • that are combined in a fixed ratio
  • compounds have different characteristics from elements
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7
Q
  1. What elements make up 96% of living matter?
A
  • carbon (C)
  • hydrogen (H)
  • oxygen (O)
  • nitrogen (N)
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8
Q
  1. Which elements make up most of the remaining 4% of living matter?
A
  • Calcium (C)
  • Potassium (K)
  • Sodium (Na)
  • Phosphorous (P)
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9
Q
  1. Which elements are only required by the organism in minute quantities?
    They make up 0.01% of living matter
A
  • Iron (Fe)
  • Iodine (I)
  • Selenium (Se)
  • Zinc (Zn)
  • THEY ARE CALLED TRACE ELEMENTS
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10
Q
  1. What is the name given to the condition of iodine deficiency in the body?
A
  • hypothyroidism is when there is an iodine deficiency in the body
  • it leads to Goitre (an enlargement of the thyroid gland)
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11
Q
  1. What is Iodine?
A
  • it is an essential trace element for the production of thyroid hormones
  • thyroxine and triiodothyronine are examples of thyroid hormones
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12
Q
  1. What is the name given to a condition caused by an Iron Deficiency?
A
  • Anaemia
  • Iron (Fe) is a part of the haemoglobin structure
  • it holds oxygen in the haemoglobin molecule
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13
Q
  1. What does each element consist of?
A
  • a specific atom
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14
Q
  1. What is an atom?
A
  • it is the smallest unit of matter that still retains the properties of an element
  • an element and it’s atom have the same symbol
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15
Q
  1. What are atoms composed of?
A
  • smaller parts called subatomic particles
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16
Q
  1. What are the three types of Subatomic Particles?
A
  1. Neutrons: no electrical charge (0)
  2. Protons: positively charged (+1)
  3. Electrons: negatively charged (-1)
17
Q
  1. Which two subatomic particles are identical in mass

What is their mass?

A
  • protons and neutrons are identical in mass
  • their mass is 1.7x10-24g
  • this is equal to 1 Dalton
18
Q
  1. Why is the mass of electrons considered negligible?
A
  • it is 1/2000 of the mass of a proton or a neutron
19
Q

19.Where are protons and neutrons found?
What are they surrounded by?

A
  • in an atomic nucleus
  • they are surrounded by an electron cloud
20
Q

20.What is the atomic number of an atom?
Why does it exist?

A
  • the atomic number is equal to the number of protons in the element
  • it is equal to the number of electrons
  • it is unique to each element
  • it is written as a subscript to the left of the symbol
  • it exists because various elements differ in their number of subatomic particles
21
Q
  1. What is the Mass Number of an element?
A
  • it is the sum of the protons and the neutrons in the nucleus of an atom
  • it is an approximation of the atomic mass of an atom
  • it is given in Daltons
  • the atomic mass is the approximation of the mass number
  • it is written as a superscript to the left of the symbol
22
Q
  1. How do we work out the number of neutrons in an element?
A

mass number (number of protons+neutrons)
MINUS the atomic number (number of protons)

23
Q
  1. What is the Atomic Mass?
A
  • it is the atom’s total mass
  • it is equal to the mass number (in Daltons)
  • it is equal to the sum of the protons and the neutrons
24
Q
  1. What are Isotopes?
A
  • they are different forms that atoms of a given element may occur in
  • they have a different number of neutrons in the atomic nucleus
  • this means they have a different mass number from one another
  • they have the same number of protons
  • this means they have the same atomic number
25
Q
  1. What are Radioisotopes?
A
  • they are radioactive isotopes
  • they are unstable
  • they spontaneously decay to give off particles and energy
  • they are used in nuclear medicine and imaging

EG: C14, H3

26
Q
  1. Name some Clinical Applications of Radioisotopes?
A
  • disease diagnosis (imaging)
  • disease treatment (I131 is used for thyroid cancer treatment and for treating hypothyroidism)
  • this radioisotope needs to release radioactive energy into the thyroid gland that it enters
  • assessment of degree of disease severity
  • treatment monitoring
27
Q
  1. What is Nuclear Medicine Imaging?
A
  • it is based on the use of radioactive isotopes
  • a PET scan is an example
  • this scan is more accurate than a CT scan
  • it can pick up medical abnormalities in their earlier stages
  • a PET scan is an imaging technique that produces a 3D image of the functional processes occurring in the body
  • it is the detection of the y-rays that are emitted by a radioisotope
  • this is known as a tracer
  • these y-rays are introduced into the body as part of a biologically active molecule (Fluoro deoxy glucose)
  • the reason this is effective is because cancer cells eat glucose
  • they eat much more glucose than regular cells
  • this is because they are reproducing much quicker
  • they multiply in the form of a tumour (an indistinguishable single cell)
28
Q
  1. What is the chemical behaviour of an atom defined by?
A
  • its electron configuration
29
Q
  1. What is the definition for Electron Configuration?
A
  • it is the distribution of an atom’s electrons in shells
30
Q
  1. What table shows the electron distribution for all the elements?
A
  • the Periodic Table