B4-The Processes of Life

Question 1

Cells- What is DNA?

Answer 1

DNA molecules are in the form of a double helix and contain the genetic code

Question 2

Cells- What are Organelles ?

Answer 2

Organelles are the different parts of the Cells structure.They do different jobs within the cell and work together to allow the cell to perform a specific function.

Question 3

Animal Cells -What is a Cytoplasm?

Answer 3

A Cytoplasm is where most chemical reactions take place,including anaerobic respiration,the production of enzymes and other proteins

Question 4

Animal Cells -What is Mitochondria?

Answer 4

A Mitochondria contains the enzymes needed for aerobic respiration

Question 5

Animal Cells -What is a Nucleus ?

Answer 5

A Nucleus contains the DNA that carries the genetic code for making enzymes and other proteins used in all chemical reactions in the cell

Question 6

Animal Cells- What is Cell Membrane ?

Answer 6

A Cell Membrane allows chemicals like gases and water to pass in and out freely,preventing other chemicals from leaving or entering the cell

Question 7

Plant Cells -What is a Cell Wall?

Answer 7

A Cell Wall is made of cellulose to strengthen

Question 8

Plant Cells -What is a Permanent Vacuole?

Answer 8

A Permanent Vacuole helps support the cell

Question 9

Plant Cells- What is a Chloroplast ?

Answer 9

A Chloroplast contains the green pigment,chlorophyll (which absorbs light energy), and some enzymes needed for photosynthesis

Question 10

Microbial Cells - What is a Cell Wall of a Microbial Cell Made up of ?

Answer 10

A Cell Wall of a Microbial Cell is NOT made of Cellulose but of other materials such as protein

Question 11

Microbial Cells- What is the structure of DNA in a Microbial Cell?

Answer 11

In a Microbial Cell, DNA is in a circular structure NOT in a Nucleus and NOT as Chromosomes

Question 12

Enzymes - What are Enzymes ?

Answer 12

Enzymes are molecules made from Protein that speed up the rate of Chemical Reactions in Cells (i.e. They’re Catalysts in living things). Cells produce Enzymes according to the instructions carried in the Genes (DNA)

Question 13

Enzymes-What is the optimum temperature of an Enzyme ?

Answer 13

The specific temperature that Enzymes need to work at is called their Optimum. Different Enzymes have different Optimum temperatures to work.At low temperatures ,small increases in temperature cause a rise in the frequency and energy of collisions between reactants and Enzymes,so the rate of reaction increases.

Question 14

Enzymes- What happens when the Optimum temperature is reached?

Answer 14

When the Optimum Enzyme Activity is reached,the Enzymes start to get damaged,so the reaction starts to slow down.Eventually the Enzymes structure is permanently destroyed and it starts working,or in other words it becomes denatured

Question 15

The Lock and Key Model- What is the Lock and Key Model?

Answer 15

Only a Molecule with correct shape is able to fit into and Enzyme. This is a little like a key (the molecule) fitting into a lock (the enzyme). Once the Enzyme and Molecule are linked, the following happens :

1. The reaction takes place
2. The products are released
3. The process is able to be repeated

Question 16

The Active Site - What is the Active Site?

Answer 16

The Active Site is the place where the molecule is the place where the molecule fits into the Enzyme. Each individual Enzyme has a different shape,so its very specific.

Question 17

The Active Site - How can the shape of the Active Site be changed irreversibly?

Answer 17

The shape of the Active Site can be changed irreversibly by …
• Heating the Enzyme above its optimum temperature
• Altering the Ph. level
This means that the molecule can’t fit and the reaction cannot take place.

Question 18

Respiration - What is Respiration ?

Answer 18

Respiration is the release of energy from chemicals from food in all living cells. There are two types of respiration:
• Aerobic
• Anaerobic

Question 19

Aerobic Respiration- What is Aerobic Respiration ?

Answer 19

Aerobic Respiration is a form of Respiration that releases energy inside living cells by breaking down Glucose and combining products with Oxygen.

Question 20

Aerobic Respiration- Word Equation

Answer 20

Glucose + Oxygen = Carbon Dioxide + water + Energy released

Question 21

Aerobic Respiration - Symbol Equation

Answer 21

C6H12O6 + 6O2 → 6CO2 + 6H2O

Question 22

Aerobic Respiration- How it works and what it needs

Answer 22

Aerobic Respiration needs Oxygen and occurs in animal Cells,plants and in many other microbial cells.
Energy released is used in many chemical reactions which include ….
• Movement e.g. the contraction of muscles when running
• Synthesis of large molecules from smaller ones, e.g. chlorophyll from glucose

Question 23

Aerobic Respiration- What is Active Transport ?

Answer 23

Active Transport of some chemicals molecules across a cell membrane

Question 24

Anaerobic Respiration- What is Anaerobic Respiration?

Answer 24

Anaerobic Respiration releases energy inside the cytoplasm of living cells by breaking down Glucose molecules without the use of Oxygen

Question 25

Anaerobic Respiration-Word Equation for Anaerobic Respiration in Plant Cells and some Microbial Cells

Answer 25

Glucose = Carbon Dioxide +Ethanol + Energy released

Question 26

Anaerobic Respiration-Word Equation for Anaerobic Respiration in Animals and some Bacteria

Answer 26

Glucose = Lactic Acid

Question 27

Anaerobic Respiration- How does it work and what does it need?

Answer 27

Anaerobic Respiration occurs in coditions of very low Oxygen or where no Oxygen is present. For Example…

• When cells of plant roots are in waterlogged soil ,e.g. rice plants
• In muscle cells of Humans during vigorous exercise, e.g. a 100M sprint
• In Bacterial cells inside a puncture wound

Question 28

Anaerobic Respiration- Which is more efficient, Anaerobic or aerobic respiration ?

Answer 28

Aerobic respiration is more efficient because it releases much more energy per Glucose molecule (19 times more) than anaerobic Respiration