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Questions and Answers
Which characteristic of carbon is MOST significant in its ability to form a wide array of stable compounds?
Which characteristic of carbon is MOST significant in its ability to form a wide array of stable compounds?
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Which of these processes is NOT considered a primary method for the formation of elements?
Which of these processes is NOT considered a primary method for the formation of elements?
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Why are silicon-silicon (Si-Si) bonds relatively weak compared to carbon-carbon (C-C) bonds?
Why are silicon-silicon (Si-Si) bonds relatively weak compared to carbon-carbon (C-C) bonds?
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What are the two elements primarily formed immediately following the Big Bang?
What are the two elements primarily formed immediately following the Big Bang?
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Why are extended chains of nitrogen atoms considered very unstable?
Why are extended chains of nitrogen atoms considered very unstable?
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What causes the core temperature of the star to rise after the exhaustion of hydrogen?
What causes the core temperature of the star to rise after the exhaustion of hydrogen?
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What is a KEY property of boron that limits the stability of its compounds?
What is a KEY property of boron that limits the stability of its compounds?
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Which of the following is NOT a reason why certain elements are not preferentially incorporated into living cells?
Which of the following is NOT a reason why certain elements are not preferentially incorporated into living cells?
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What is the key energy barrier that must be overcome by nuclei during fusion reactions in stars?
What is the key energy barrier that must be overcome by nuclei during fusion reactions in stars?
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What is the primary source of light emitted by most visible stars?
What is the primary source of light emitted by most visible stars?
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Which event is primarily responsible for the release of elements formed in the center of stars?
Which event is primarily responsible for the release of elements formed in the center of stars?
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What happens to a star after its hydrogen supply is exhausted?
What happens to a star after its hydrogen supply is exhausted?
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What is the primary mechanism for the creation of elements larger than iron?
What is the primary mechanism for the creation of elements larger than iron?
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Which of the following best describes why even-numbered elements are generally more abundant than odd-numbered elements?
Which of the following best describes why even-numbered elements are generally more abundant than odd-numbered elements?
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What process is essential for the synthesis of transuranium elements, such as Californium?
What process is essential for the synthesis of transuranium elements, such as Californium?
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What is the approximate percentage of carbon atoms found on Earth?
What is the approximate percentage of carbon atoms found on Earth?
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Which group of elements primarily constitutes the 'bulk elements' of living cells?
Which group of elements primarily constitutes the 'bulk elements' of living cells?
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What is a significant feature of the 'major elements' found in organic compounds within cells?
What is a significant feature of the 'major elements' found in organic compounds within cells?
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Which set of elements are most abundant in the Earth's composition, in order of abundance?
Which set of elements are most abundant in the Earth's composition, in order of abundance?
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What is the primary reason carbon has a unique ability to form a wide range of compounds?
What is the primary reason carbon has a unique ability to form a wide range of compounds?
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Which of the following is NOT a ‘trace’ element commonly found in cells, according to the text?
Which of the following is NOT a ‘trace’ element commonly found in cells, according to the text?
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Which of the following is a characteristic of the ‘major’ elements that are fundamental to organic compounds within cells?
Which of the following is a characteristic of the ‘major’ elements that are fundamental to organic compounds within cells?
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Study Notes
Biochemistry 151: Lecture 1 - Elemental Composition of Cells
- Course title: BCHEM 151: Biochemistry
- Lecturer: Amma Larbi, PhD
- Lecture: Elemental Composition of Cells
Study Objectives
- Understanding the origin of elements
- Identifying elements found in living cells
- Explaining why certain elements are present in cells while others are excluded
- Exploring why carbon forms so many compounds
Introduction
- Living cells and organisms are composed of intricately organized elements forming recognizable structures.
- Atoms/elements are the fundamental building blocks in biochemistry, not cells.
Origin of Elements
- Elements are formed through:
- The Big Bang
- Fusion reactions in stars
- Artificial synthesis
The Big Bang Theory
- An infinitely hot, dense primordial matter exploded, forming hydrogen and helium
- Gravitational forces caused gas clouds to collapse into stars
- Elements beyond hydrogen and helium are created in stars' cores and released upon their explosion. (i.e. supernovae)
Fusion Reactions in Stars
- Very high temperatures are necessary to overcome electrostatic repulsion between positive charged nuclei
- Fusion reactions radiate heat and light to form stars from gas clouds
- Stars release enormous amounts of energy, causing explosions
Elements Utilized to Form Cells
- Over 117 elements exist, but fewer than one-third are found in cells.
- Common elements: oxygen, iron, silicon, magnesium, carbon.
- Carbon is present in a much lower percentage compared to other common elements
- Main ions in sea water and in blood plasma are similar (e.g., Cu2+, Mg2+, Ca2+, Na+, K+, etc)
Major (Bulk) Elements of Cells
- Carbon (C), Hydrogen (H), Oxygen (O), Nitrogen (N), Phosphorus (P), Sulfur (S)
- Found in organic compounds within cells
Minor (Trace) Elements of Cells
- Na, K, Mg, Ca, B, V, Mn, Fe, Co, Ni, Cu, Zn, Si, Se, Cl, Br, and Cr
- Found in fluids bathing cells
Striking Features of Major Elements
- Majority are p-block elements
- Able to form covalent bonds
- Non-metals
- Have smaller atomic numbers/sizes
- Not excessively reactive or inert.
Why Carbon is Unique
- Ideal size to form stable covalent bonds
- Tetravalent (four valence electrons)
- Can form catenation (bonding with itself and other atoms)
- Ability to form multiple bonds
Other Elements with Three or More Bonds (e.g., Silicon)
- Belongs to group IVA (tetravalent)
- Larger atomic size, causing weakly bonded silicon-silicon (Si-Si) bonds compared to carbon.
- Silicon-oxygen (Si-O) bonds are stable and form chains.
- Silicon is far more abundant than carbon in Earth's crust but carbon is preferentially used in living cells
Nitrogen
- 5 valence electrons when forming N-N bonds
- Low bond energy compared to C-C
- Lone pair electrons on each nitrogen atom reduce bond energy of N-N bonds.
- Chains of nitrogen atoms are unstable
Boron
- 3 valence electrons; Forms electron deficient instead of covalent molecules
- Limited stability of boron compounds
Reasons Other Elements Were Not Incorporated
- Artificial nature of some elements
- Inert nature of some elements
- Toxic nature of some elements
- Radioactivity of some elements
Non-essential Elements with Beneficial Uses
- Lithium compounds (e.g. Li2CO3): Treatment of schizophrenia
- Platinum/gold complexes: Anticancer/anti-arthritis
- Kaolin (aluminium-containing): Anti-diarrhoeal
Further Research
- YouTube videos on stellar hypothesis (Big Bang to Present Day, Beyond the Big Bang Explosion)
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Description
This quiz explores the fundamental elements that compose living cells, delving into their origins and the reasons behind their presence in biological structures. Learn about the processes through which elements are formed, from the Big Bang to stellar fusion, and understand the significance of carbon in biochemistry.
