Life At Cellular Level

Question 1

What is Photosynthesis, give a word equation as well

Answer 1

Photosynthesis is the process were sunlight is used to produce glucose.
Carbon dioxide+water———> (light and chlorophyll) glucose+ oxygen

Question 2

What is the process of photosynthesis in terms of the light dependant and independent phases?

Answer 2

The LIGHT DEPENDANT phase takes place in the THYLAKOIDS of the chloroplast. Light is ABSORBED through the CHLOROPHYLL PIGMENT found in the chloroplasts. This light energy SPLITS the H2O molecule in to O2 and H+. The HYDROGEN goes into the LIGHT INDEPENDENT phase and the OXYGEN is DIFFUSED via the STOMATA. The LIGHT INDEPENDANT phase takes place in the STROMA of the chloroplasts. The H+ combines with the CO2 after a series of REACTIONS to form GLUCOSE.

Question 3

Explain how water availability affects the light INDEPENDENT phase

Answer 3

The amount of water available to the plant will affect the AMOUNT OF H+ PRODUCED because if there is NOT ENOUGH , the plant will be DEPRIVED OF H+, causing the glucose molecule to NOT BE CONSTRUCTED. Increased amounts of water will only increase the production of H+ to a limit because water can only be split into H+ and O2 to a limit. After the limit has been reached more water won’t be made.

Question 4

Explain how light intensity affects the light DEPENDANT phase

Answer 4

High amounts of light intensity would INCREASE the rate of the light DEPENDENT phase because more light energy will be available to split the H20 molecule and produce more ATP and NADPH, speeding up the process. This will only be beneficial to a certain extent because the rate won’t further increase due to other limiting factors like CO2 availability.

Low amounts of light intensity reduces the rate of the light DEPENDENT phase because there isn’t a sufficient amount of energy to split the water molecule, leading to less ATP and NADPH being produced, slowing the overall rate of photosynthesis

Question 5

Explain how the factor of chloroplasts affects the rate of photosynthesis

Answer 5

The number of chloroplasts affects the rate of photosynthesis because chloroplasts are the site of photosynthesis. MORE chloroplasts means that the plant has more sites available to CAPTURE LIGHT ENERGY AND CONVERT IT INTO CHEMICAL ENERGY DURING THE LIGHT DEPENDANT PHASE. This can increase the overall efficiency of photosynthesis.

Fewer chloroplasts would LIMIT the plants ability to photosynthesise efficiently, reducing energy production.

Question 6

Explain how the concentration of chloroplasts affect photosynthesis.

Answer 6

A higher concentration for chloroplasts increase surface area available for capturing light energy. This greater surface area allows more light DEPENDANT reactions to occur, bossing the overall rate of photosynthesis.

With a lower concentration of chloroplasts, surface area for absorbing light is reduced, meaning fewer reactions can take place at once. This lowers the rate of energy production, slowing down photosynthesis.

Question 7

Explain the structure of chloroplasts and there functions

Answer 7

Chloroplasts contain CHLOROPHYLL PIGMENT which helps in absorbing LIGHT, enabling photosyntehsis.
The THYLAKOID filled with CHLORPHYLL. Provide LARGE SURFACE AREA for MAXIMUM LIGHT ABSORBTION for the light REACTIONS to occur.
These reactions will CONVERT SOLAR ENERGY ITO CHEMICAL POTENTIAL ENERGY. The LIQUID STROMA CPTURES CO2 in order to make GLUCOSE and other CARBON COMPOUNDS.
The DOUBLE MEMBRANE is CLEAR, allowing light to easily to flow through, as well as controlling at WHAT GOES I AND OUT OF THE CHLOROPLASTS.

Question 8

What is cellular respiration

Answer 8

Cellular respiration is the process which OCCURS IN THE MITOCHONDRIA. Cells use oxygen to TURN GLUCOSE into ENERGY (ATP) for the cell. There are two types of cellular respiration, AEROBIC and ANAEROBIC RESPIRATION

Question 9

Explain the process of AEROBIC respiration

Answer 9

GLUCOSE+OXGYEN——> 36ATP+WATER+CARBONDIOXIDE

Aerobic respiration is respiration WITH OXYGEN. The GLUCOSE molecule is broke down in several stages, glycolysis, Krebs cycle and electron transport chain to PRODUCE WATER, CARBON DIOXIDE AND 36ATP PER GLUCOSE MOLECULE. Because oxygen is present more energy is produced, 36ATP/38ATP as compares to ANAEROBIC respiration 2ATP.
Because oxygen is needed, the energy is produced a lot more SLOWLY.
An advantage of aerobic respiration is that it does not produce any harmful waste products such as LACTIC ACID which can be very harmful to the cell if not REMOVED.

Question 10

Explain the process of ANAEROBIC RESPIRATION

Answer 10

GLUCOSE——>2ATP+LACTIC ACID

Anaerobic respiration is respiration WITHOUT OXYGEN and occurs in the CYTOPLASM. Glucose is broken down through the process of glycolysis, producing 2ATP and LACTIC ACID.
An ADVANTAGE of this respiration is that it allows the cell to FUNCTION even with 0% CONCENTRATION. Because oxygen is NOT NEEDED, the 2ATP is produced a lot faster as compared to aerobic respiration.
A DISADVANTAGE of is respiration is that it produces harmful waste products; lactic acid.
A build up of lactic acid can DAMAGE THE HEART MUSCLE if NOT REMOVED because it is so TOXIC.

Question 11

Explain mitosis

Answer 11

Mitosis is the process where the PARENT CELLS DIVIDES INTO TWO DAUGHTER CELLS. It occurs in the SOMATIC/BODY CELLS as a part of the cell division cycle. The DAUGHTER CELLES ARE IDENTICAL TO THE PARENT CELL. Mitosis is important for the growth and repair of cells, as well as to MAINTAIN SA:V RATIO; as the cell grows larger, the volume increases more than the SA.

Question 12

Explain the purpose and process of DNA replication

Answer 12

DNA replication occurs BEFORE MITOSIS during the INTERPHASE of the cell cycle. The purpose of DNA replication is to produce TWO IDENTICAL COPIES OF THE CELLS DNA. This is necessary so each NEW CELL as the CORRECT REQUIRED GENETIC INFORMATION TO CARRY OUT LIFE FUNCTIONS

It’s process beings with the ENZYME HELICse UNZIPPING the double helix CREATING A TEMPLATE STRANDS. DNA polymerase adds the complementary nucleotides to each template strand, forming two new double helicases. This ENSURES DNA continuity, as each daughter DNA molecule retains one parental strand.

Question 13

Explain why DNA is said to be semi-conservative

Answer 13

DNA is a semi-conservative process, meaning each NEW DNA molecule consists of ONE ORIGINAL and newly synthesised strand.

Question 14

Explain Osmosis

Answer 14

Osmosis is the DIFFUSION of water across a SEMI-PERMEABLE membrane from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION. This process requires NO ENERGY, therefor it is form of PASSIVE TRANSPORT.

The water enters from the SOIL through the ROOT HAIRS via osmosis. The soil emits have a HIGH CONCENTRATION OF WATER to move into the SEMI-PERMEABLE MEMBRANE and into the ROOT CELL which have LOW CONCENTRATION OF WATER.

Question 15

What is Diffusion

Answer 15

Diffusion is a form of PASSIVE TRANSPORT, where the substance from an area of HIGH CONCENTRATION to an area of LOW CONCENTRATION GRADIENT until the substance has been evenly diffused.

Question 16

What are Enzymes?

Answer 16

Enzymes are biological catalysts which speed up a chemical reaction without not being used up in the reaction themselves.

Question 17

How are Enzymes Specific?

Answer 17

They are specific because they only work on type of reaction due to the shape of their active sites.

Question 18

Explain the shape of a enzyme and how a change in shape will affect the collision

Answer 18

Substrates/reactants are shaped to fit into the active site which is the inner shape of the enzyme. For the reaction to work the substrate/reactant must collided correctly with the active site, so if the shape has been altered this cannot occur.

Question 19

How are Enzymes reuse able?

Answer 19

Enzymes are reuse able because once the product is formed it is then realised form the active site. The enzyme is unchanged, this it can be reused in another chemical reaction.

Question 20

Explain how Temperature affects Enzyme Activity

Answer 20

At LOW temperatures both the enzyme and substrate/reactants move slowly therefore there are less successful collisions between the enzymes active site and the reactants therefore slow rate of chemical reactions, causing less product to be formed.

At OPTIMAL temperature both substrates/reactants and enzyme move more quickly therefore more successful collisions therefore faster rate of reaction occur, causing more product to be formed.

At HIGH temperatures the enzymes active site denatures causing it to change shape. This means the substrate/reactants can no longer fit into the active site and the enzyme stops working so the reaction rate decreases, causing either no product or very little product to be formed.

Question 21

Explain how pH affects Enzyme activity

Answer 21

Enzymes work best at a specific pH. If the pH changes, the enzyme shape changes, thus causing the substrate/reactants to no longer fit into and the reaction rate decreases, hence less product or no product is formed. So if the enzyme is not at its OPTIMAL pH then the enzyme shape will change.

Question 22

Explain how pH affects Enzyme activity

Answer 22

Enzymes work best at a specific pH. If the pH changes, the enzyme shape changes, thus causing the substrate/reactants to no longer fit into and the reaction rate decreases, hence less product or no product is formed. So if the enzyme is not at its OPTIMAL pH then the enzyme shape will change.

Question 23

Explain how Substrate/Reactant concentration affects Enzyme Activity?

Answer 23

At LOW substrate/reactant concentration there is less substrate/reactant so less chance of them colliding with the enzymes active site therefore a slow rate of reaction, hence less or no product is formed.

At OPTIMAL substrate/reactant concentration there is more substrate/reactants so there is a greater change of them having successful collisions with the enzymes active site therefore a faster rate of reaction, leading to more product being formed.

At HIGH substrate/reactant concentration he enzyme concentration becomes a limiting factor This means that there isn’t enough enzyme active sites for all the substrate/reactants to fit into therefore the rate of reaction LEVELS OFF.

Question 24

Explain how Enzyme Concentration affects Enzyme activity

Answer 24

At LOW enzyme concentration there are less active sites for the substrates/reactants to fit into so there is a slower rate of reaction and less product is produced.

At OPTIMAL enzyme concentration there are more active sites for the substrates/reactants to fit into so the rate of reaction is faster and more product is produced.

At HIGH enzyme concentration the substrate/reactants become a limiting factor. This means that there are not enough substrate /reactants for the enzymes active sites, therefore the rate of reaction LEVELS OFF.