chemical and cellular basis of life - structured Flashcards
How many elements are recognized in nature?
92 elements
How many elements are essential to continue a healthy life and reproduction?
20-25% of elements
How many elements are essential for humans?
25 elements
How many elements are essential for plants?
17 elements
What elements make up 96% of living matter?
C H O N
What elements make up the remaining 4% of the mass of an organism?
Ca, P, K, and S
What elements are found in minute amounts in living matter?
Co Cu Cr Cl Na Mg B F Fe I
Describe the chemical nature of a water molecule
It is a vital, inorganic, small, polar and angular molecule
state the reasons why life couldn’t exist on this planet without water.
- It is a vital chemical constituent of the living cell
- It provides a biological medium for all organisms
What properties of a water molecule provide the ability to render the vitality?
The physical and chemical properties of a water molecule
What ability do the physical and chemical properties of a water molecule provide?
The ability to render the vitality
Write 3 chemical/physical properties of water
Being a small, polar, and angular molecule
Write the features of a water molecule
Being a small, polar, and angular molecule
How do the properties of water arise?
The properties of water arise due to the hydrogen bonds between different water molecules
What is polarity?
Polarity is the uneven charge distribution within a molecule
Why are water molecules considered “polar”?
In water molecules, the O atom is slightly negative and the H atom is slightly positive, thereby making it polar
What are hydrogen bonds?
Hydrogen bonds are the weak attractions between the slightly polar H atom of one water molecule and the slightly polar O atom of the adjacent molecule
What role do hydrogen bonds play?
Hydrogen bonds play a major role in maintaining all the properties of water
How do the properties of water arise?
They arise due to the hydrogen bonds between different water molecules
Describe the nature of water’s hydrogen bonds
When water is in liquid form, its hydrogen bonds are very fragile. They form, break and reform with great frequency.
Write the major properties of water that helps maintain life on earth?
- Cohesive behavior
- Ability to moderate temperature
- Versatility as a solvent
- Expansion upon freezing
(CAVE)
Write the properties of water related to functions
- Cohesive behavior
- Ability to moderate temperature
- Versatility as a solvent
- Expansion upon freezing
(CAVE)
What is cohesion?
Cohesion is the attraction between water molecules due to hydrogen bonding
What is adhesion?
Adhesion is the attraction between water molecules and other substances
What is the function of both cohesion and adhesion?
Allows water to act as a transport medium
What properties of water allows it to act as a transport medium?
Both the properties of cohesion and adhesion
Write an examples for cohesive behavior
Due to cohesion between water molecules, water and dissolved substances such as minerals and nutrients are transported as a continuous column against gravity.
Water has a high surface tension. This ability is given to water molecules, due to cohesion between the water molecules. In an aquatic system, upper surface water molecules are attracted by lower surface molecules and it forms a water film.
Small insects ( e.g. water skaters ) can walk on the surface of a pond.
Write an example for adhesive behavior
Adhesion between water molecules and cell walls also helps in conduction of water and dissolved substances
Write examples for water’s ability to moderate temperature
Because of high specific heat, water functions as a thermal buffer in living systems and aquatic bodies during temperature fluctuations on earth
Due to the high heat of vaporization, with the minimum loss of water an organism can release much heat energy.
e.g. Therefore, body surface of an organism maintained as cool surface.
Prevent from overheating
Evaporation of sweat from human skin helps to maintain the body temperature at constant level.
Transpiration in plants keeps the plant body surface as a cool surface and prevent from becoming too warm in the
sunlight.
What are the functions of high specific heat?
Because of high specific heat, water functions as a thermal buffer in living systems and aquatic bodies during temperature fluctuations on earth
What is the function of high heat of vaporization?
Because of high heat of vaporization, with the minimum loss of water an organism can release much heat energy.
This helps organisms to cool their body surfaces.
Give examples for high heat of vaporization
This helps organisms cool their body surfaces
Evaporation of sweat from human skin (helps maintain body temperature at a constant level)
Transpiration in plants (helps keep plant body surface cool and prevents from becoming too warm in the sunlight)
What is the function of evaporation of sweat from human skin ?
helps maintain body temperature at a constant level
What is the function of transpiration in plants
helps keep plant body surface cool and prevents from becoming too warm in the sunlight
What substances are transported as a continuous column through xylem against gravity in cohesion
Water
Dissolved substances such as minerals and nutrients
How is the ability of having a high surface tension given to water?
due to the cohesion between water molecules.
Give an example for high surface tension in water
In an aquatic system, the upper surface water molecules are attracted by the lower surface water molecules and it forms a water film.
Small insects (EX: WATER SKATERS) can walk on the surface of a pond this way
What does the adhesion between water molecules and cell walls help in?
the conduction of water and dissolved substances
How are Water and dissolved substances such as minerals and nutrients transported?
As a continuous column through xylem against gravity
How is water and dissolved substances conducted?
Through the adhesion between water molecules and cell walls
Write the relationship between the temperature and the density of a substance generally.
Generally, when the temperature of any substance increases, their density reduces. When the temperature of any substances decreases, their density increases.
Write an example for water’s property of expansion upon freezing
It is an important property of water in polar regions, where, organisms in aquatic bodies can survive during the winter.
Write an example for water’s property of versatility as a solvent
Polar molecules (e.g. Glucose), non-polar ionic (e.g. NaCl), both polar and ionic (e.g. lysozymes) can dissolve in water
When does water begin to freeze and form crystalline lattices called ice cubes?
When the temperature of water falls below 4c
What happens when the temperature of water falls below 4c?
It begins to freeze and forms a crystalline lattice named ice cubes
What are ice cubes?
They are a crystalline lattice formed when water begins to freeze when the temperature of water drops below 4c
When does water have the maximum density
At 4c
Why does ice float on the surface of water bodies?
Because water has the maximum density at 4c
Why is expansion upon freezing important for water?
It is important for water in polar regions where organisms in aquatic bodies can survive during the winter
How is the ability of versatility as a solvent given to water?
Due to their polarity
What ability is given to water due to their polarity
Versatility as a solvent
Give examples for substances that dissolve in water
Ionic Compunds (Nacl)
Polar molecules (Glucose)
Molecules having both polar and ionic regions (Lysozymes)
Why do ionic compunds, polar molecules and molecules having both polar and ionic regions dissolve in water?
Because water molecules surround each of these solute molecules and form hydrogen bonds with them
What does the solubility of a solute depend on?
Polarity
What doesn’t the solubility of a solute depend on?
Their ionic nature
What are the main organic compounds of organisms?
Carbohydrates
Lipids
Proteins
Nucleic Acids
Write the most abundant organic compound on earth
Carbohydrates
What is the major elemental composition of carbohydrates?
C , H , O
What is the H:O ratio of carbohydrates
2:1
What is the H:O ratio of carbohydrates similar to
Water
Write the general formula of carbohydrates
Cx(H20)y
What are the 3 major groups of carbohydrates
Monosaccharides
Disaccharides
Polysaccharides
What do carbohydrates include generally?
Sugars (Monosaccharides and disaccharides)
Polysaccharides
What is metabolism?
Metabolism is the sum of all biochemical reactions. It consists of all anabolic and catabolism reactions
What does metabolism consist of?
It consists of all anabolic and catabolism reactions
What is catabolism?
Catabolism is breaking down complex molecules into simple molecules by releasing free energy.
What type of reaction is catabolism?
Exergonic
Why is catabolism considered an exergonic reaction?
Because it releases free energy in its process
What is anabolism?
Anabolism is making complex molecules from simple molecules by absorbing free energy
What type of reaction is anabolism?
Endergonic
Why is anabolism considered an endergonic reaction?
Because in its process, it absorbs free energy
Why is ATP considered the “universal currency of energy transactions”?
Because it acts as the energy carrier in all living organisms including the simplest bacteria
Where does ATP act as an energy carrier?
It acts as the energy carrier in all living organisms including the simplest bacteria
What is energy?
Energy is the capacity to do work
Why do all living organisms require energy for?
For their living processes in many ways
ex: Bioluminescence
Beating of cilia and flagella
Electrical Discharges
Synthesis of substances
Active transport of substances across plasma membrane
Transmission of nerve impulses
Muscle contraction
Give examples for the processes all living organisms require energy for
Bioluminescence
Beating of cilia and flagella
Electrical Discharges
Synthesis of substances
Active transport of substances across plasma membrane
Transmission of nerve impulses
Muscle contraction
What are the steps of the overall idea of energy relations of a living system on the biosphere?
- Energy flows into biological systems from the environment through solar radiation (primary energy source is the sun)
- Light energy is captured by the photosynthetic pigments (chlorophyll) in the cells by the process of photosynthesis
Then, it is stored as chemical energy in organic compounds such as carbohydrates
- Captured energy in organic food is transformed into chemical energy in ATP by a process called cellular respiration
- The energy stored in ATP is utilized in many energy requiring process.
What is the primary energy source of the biosphere?
The sun
How does energy flow into biological systems from the environment?
through solar radiation
How is light energy is captured in the cells?
by the photosynthetic pigments (chlorophyll) by a process photosynthesis
What is the process used to capture light energy is captured by the photosynthetic pigments (chlorophyll) in the cells?
Photosynthesis
How is the chemical energy produced during photosynthesis stored in cells?
It’s stored as chemical energy in organic compounds such as carbohydrates
How is captured energy in organic food is transformed into chemical energy in ATP?
by a process called cellular respiration
What is cellular respiration?
It is a process by which the captured energy in organic food is transformed into chemical energy in ATP
How is the energy stored in ATP utilized?
In various energy requiring processes
What is the cell cycle?
The sequence of events that take place in the life o a cell from the end of one cell division to the end of the next cell division is referred to as the cell cycle
At the end of the cell division, what is produced in mitosis?
2 genetically identical daughter cells resembling the parent cell
What are the two major phases the eukaryotic cell cycle is divided into?
Interphase
M-phase/ mitotic phase
What is the longer phase of the cell cycle?
Interphase
What percentage of the cell cycle does the interphase cover?
About 90% of the cell cycle
What are the 3 phases the interphase is divided into?
G1 phase
S phase
G2 phase
