Crowdly

When calculating Surface Area to Volume ratios (SA:V), the following formulas are used:

Sphere:

Surface area = 4πr²
Volume = 4/3πr³
Where π = 3.14 and r = radius of the sphere

Cube:

Surface area = 6 x (length x depth)
Volume = length x depth x height

You have been given two cell samples:

Cell A is a spherical cell with a radius of 1.5 µm.
Cell B is a cube-shaped cell with a length, depth, and height of 2 µm.

a) What is the SA:V of Cell A?

b) What is the SA:V of Cell B?

c) Based on the above calculations, which cell (A or B) would most efficiently transport substances across the cell membrane?

Cell A has a larger SA:V ratio than Cell B, allowing the cell to transport substances across the cell membrane more efficiently.

Cell B has a larger SA:V ratio than Cell A, allowing the cell to transport substances across the cell membrane more efficiently.

Cell A and Cell B have the same SA:V ratio, resulting in equal efficiency in transport across the cell membrane.

When calculating Surface Area to Volume ratios (SA:V), the following formulas are used:

Sphere:

Surface area = 4πr²
Volume = 4/3πr³
Where π = 3.14 and r = radius of the sphere

Cube:

Surface area = 6 x (length x depth)
Volume = length x depth x height

You have been given two cell samples:

Cell A is a spherical cell with a radius of 5 µm.
Cell B is a cube-shaped cell with a length, depth, and height of 10 µm.

a) What is the SA:V of Cell A?

b) What is the SA:V of Cell B?

c) Based on the above calculations, which cell (A or B) would most efficiently transport substances across the cell membrane?

Cell A has a larger SA:V ratio than Cell B, allowing the cell to transport substances across the cell membrane more efficiently.

Cell B has a larger SA:V ratio than Cell A, allowing the cell to transport substances across the cell membrane more efficiently.

Cell A and Cell B have the same SA:V ratio, resulting in equal efficiency in transport across the cell membrane.

Please answer all parts of the question.

Your drawing will be assessed on the following:

Please submit the scientific drawing of your cell here. It must be submitted in PDF format (.pdf).

How well it conforms to the standard conventions of scientific drawings (as outlined in your lab notes)
Inclusion of all required components
Accuracy and clarity of the drawn components
Legibility of any accompanying text.

Your submission must be a photograph of a hand-drawn cell in pencil on plain white paper. Drawings that have been generated electronically will not be accepted and will receive zero marks.

Drawing that conforms to all scientific conventions = 9 marks

The environment contains predators that a cell must evade in order to survive.

Environmental Condition 3:

Which ONE of the following options describes a single-celled organism best adapted to this environmental condition, together with an accurate justification?

The organism has a flagellum in addition to a large number of chloroplasts in the cytoplasm to produce oxygen and glucose.

The organism has a flagellum and uses passive diffusion to move away from the predators.

The organism has a flagellum, in addition to a large number of mitochondria in the cytoplasm ensuring an adequate energy supply for all cellular functions.

100%

The organism has a flagellum, in addition to specialised vacuoles to store nutrients.

The organism has a flagellum with restricted ATP supply, to conserve energy, in addition to having a thick cell wall that provides protection.

The organism has a flagellum, in addition to a high internal concentration of solutes so it does not need to extract them from the surrounding environment.

The organism has a flagellum and releases a sticky substance to trap predators.

The organism has a flagellum and alters its metabolic pathways to reduce energy consumption.

The environment contains high levels of hydrogen peroxide which is toxic to the cell.

Environmental Condition 2:

Which ONE of the following options describes a single-celled organism best adapted to this environmental condition, together with an accurate justification?

The organism increases the number of membrane proteins to minimize interactions with hydrogen peroxide.

The organism produces elevated levels of catalase and reduced levels of peroxidase to reduce hydrogen peroxide levels.

The organism produces elevated levels of protease and amylase to reduce hydrogen peroxide levels.

The organism increases the production of glycolipids to enhance membrane fluidity.

The organism increases the production of ester bonds in membrane lipids to enhance stability.

The organism uses a proton pump to break down hydrogen peroxide outside the cell and then transfer hydrogen ions into the cell.

The organism has increased numbers of peroxisomes and produces elevated levels of catalase and peroxidase.

33%

The organism has increased numbers of peroxisomes and produces elevated levels of catalase.

67%

There is no land or bodies of saltwater on the planet. The entire planet’s habitat is freshwater.

Environmental Condition 1:

Which ONE of the following options describes a single-celled organism best adapted to this environmental condition, together with an accurate justification?

The organism has a thick cell wall to prevent water loss.

The organism utilises a buffer system to stabilise the pH level, resulting in the cytoplasm becoming more acidic.

The organism has a large number of mitochondria to enable the active transport of water into the cell.

The organism has a reduced number of mitochondria to increase the rate of the active transport of ions from the cytoplasm to the surrounding environment.

The organism uses passive diffusion to absorb nutrients.

The organism has specialised vacuoles to expel excess water.

100%

The organism alters its metabolic pathways to reduce energy consumption.

The organism has a large oral groove to assist with increased water intake.