A1 (water and nucleic acids)

Question 1

What is meant by: High Specific Heat

Answer 1

Water resists temperature changes.

Question 2

What is meant by: Cohesion/Adhesion

Answer 2

Water molecules stick together and to other surfaces.

Question 3

What is meant by: Solvent Properties:

Answer 3

Water dissolves many substances due to its polarity.

Question 4

Define viscosity

Answer 4

the measure of a fluid’s resistance to flow

Question 5

what is buoyancy?

Answer 5

the upward force exerted by a fluid (such as water or air) on an object placed in it.

Question 6

what is a consequence of buoyancy for animals that live in aquatic habitats

Answer 6

any one from

1. Bony fish have an air-filled swim bladder - used to control overall density

or

2. cyanobacteria have gas vesicles which they use to adjust how close to the surface they float

Question 7

define thermal conductivity

Answer 7

the rate at which heat passes through a material

Question 8

what is a consequence of thermal conductivity on animals?

Answer 8

AQUATIC warm-blooded animals are at a much grater risk of the loss of body heat than LAND warm-blooded animals

Question 9

what are the plants two transport systems?

Answer 9

xylem (mineral ions transported in the sap)

Phloem (sap transports sucrose and other products of photosynthesis

Question 10

what is the goldilocks zone

Answer 10

the habitable zone around a star where conditions are ideal for liquid water to exist on a planet’s surface—neither too hot nor too cold. This zone is crucial for the potential development of life.

Question 11

list some substances that blood transports

Answer 11

the following get transported via the blood plasma:
1. sodium chloride
2. Amino Acids
3. Glucose
4. Fat molecules (coated in a layer of phospholipids)

5. Oxygen (transported via haemoglobin)

Question 12

Explain how the high specific heat of water contributes to the moderation of temperature in living organisms. Provide examples.

Answer 12

Water may cool air at night and warm during the day. High specific heat stabilizes ocean temperatures. This is important to life because organisms made of water are able to resist changes in their own temperature. Keeps life in balance.

Question 13

Explain how the property of cohesion in water molecules is crucial for the movement of water in plants. Include the terms transpiration and cohesion-tension theory in your explanation.

Answer 13

capillary action in plants, facilitating the movement of water against gravity. Transpiration, (the evaporation of water from the stomata) creates tension in the xylem, contributing to the upward movement of water.

Question 14

Elaborate on the importance of the solvent properties of water in biological systems, particularly in the context of cellular processes.

Answer 14

nutrient transport,
metabolic reactions
maintenance of cellular structures.

Water’s polarity allows it to dissolve polar and ionic substances, making it a universal solvent in living organisms.

Question 15

Name the term

“The process by which water moves through a plant and evaporates from aerial parts, especially leaves. Creates tension in the xylem, aiding in the upward movement of water.”

Answer 15

Transpiration

Question 16

Define the term and state why its important
“Solvent properties”

Answer 16

Definition: The ability of water to dissolve a wide range of substances due to its polar nature.

Why it’s important: Essential for various biological processes, including nutrient transport and metabolic reactions.

Question 17

DNA vs. RNA:

Answer 17

DNA (deoxyribonucleic acid): stores genetic information,

RNA (ribonucleic acid): aids in protein synthesis.

Question 18

Explain the nucleotide structure

Answer 18

phosphate group, sugar (deoxyribose or ribose), nitrogenous base.

Question 19

What are the bases that pair together?

Answer 19

A-T and G-C (DNA); A-U and G-C (RNA).

Question 20

Contrast the role of DNA and RNA in information storage and transfer within a cell. How does the structure of each molecule support its function?

Answer 20

DNA: more stable due to its double-stranded structure and the presence of deoxyribose sugar,
making it suited for long-term genetic storage.

RNA: less stable, suitable for short-term tasks like,
transferring genetic information from DNA during protein synthesis.

Question 21

Detail the experimental setup and findings of the Hershey-Chase experiment. How did this experiment contribute to our understanding of DNA as the genetic material?

Answer 21

short answer: experiment confirming that DNA, not protein, is the genetic material.

long answer: The Hershey-Chase experiment demonstrated that DNA, not protein, is the genetic material. Radioactively labeled viruses were used to infect bacteria, and only the DNA was found inside the bacterial cells, supporting the idea that DNA carries genetic information.

Question 22

What are Chargaff’s Rules and what did it influence? What method did he use?

Answer 22

The amount of adenine (A) equals the amount of thymine (T)
and
The amount of guanine (G) equals the amount of cytosine (C).

Influenced the discovery of the double helix structure of DNA.

Method: Paper chromatography