Scale of Cells

Cell Size Notes

Multiple Choice

Cells are many different sizes and shapes.

• True

• False

Multiple Choice

The structure of a cell helps with its

• function

• wants

• speed

• shape

​Cell Size

​Why are cells so small?

​

1. ​Transport of materials

   1. ​Diffusion

      1. ​less efficient over long distances

   2. ​Cytoskeleton

      1. ​Weaker and less efficient when cells are longer

2. ​Cellular communication

   1. ​Longer distances = longer communication time

   2. ​Cells use signal proteins to communicate

​Cell Size

​The efficiency of cell INCREASES as cell size DECREASES

​

• ​Oxygen transportation

• ​Waste removal

• ​Homeostasis

• ​Food transportation

• ​Signal transduction

​Surface Area to Volume Ratio

​Surface area = size of plasma membrane

​Volume = space taken up by the inner contents of a cell

​

​Relationship between surface area and volume

• ​Large surface area and Small volume = a high surface area to volume ratio

  • ​MOST efficient

• Small surface area and Large volume = low surface area to volume ratio​

  • ​LEAST efficient

Multiple Select

Select all that apply: All organisms need to be able to efficiently:

• Obtain oxygen & nutrients from environment

• Remove waste

• Maintain homeostasis (ex: body temperature)

Multiple Choice

Cells want to _________ their efficiency at carrying out life processes

• reduce

• maximize

• slow down

• prevent

Multiple Choice

Most cells are ______ because it maximizes their efficiency.

• Small

• Large

Multiple Select

Select all that apply: Cells can’t be too big because . . .

• Need to take in nutrients and release waste

• Need to move materials quickly in/out

• Inefficient if cells are large

Multiple Choice

The larger the cell, the _______ it will take to transport materials, process nutrients, or release wastes.

• Longer

• Faster

Multiple Choice

Cells are most efficient when they are _____.

• Small

• Large

• Fat

• Skinny

Multiple Choice

Surface area of a cell refers to

• the area exposed to the external environment.

• the amount of space inside of the cell.

Multiple Choice

Volume refers to

• the area exposed to the external environment.

• the amount of space inside of the cell.

​Calculating SA:V (Surface Area to Volume ratio)

​Surface Area to Volume Ratio

Multiple Choice

Cells want a _______ SURFACE AREA and a ______VOLUME.

• Small; Small

• Large; Large

• Large; Small

• Small; Large

Multiple Choice

Cells that are ____ have a greater surface area compared to volume (SA:V ratio).

• Small

• Large

Multiple Choice

CLICK ON IMAGE: Which cell would have the greatest surface area and smallest volume?

• 1um cube (smallest)

• 2um cube (middle)

• 4um cube (largest)

Multiple Choice

CLICK ON IMAGE: Which cell would have the smallest surface area and largest volume?

• 1um cube (smallest)

• 2um cube (middle)

• 4um cube (largest)

​What are the benefits of a high surface area to volume ratio?

• ​Less surface area

  • ​cell has difficulties bringing in nutrients needed by the cell

    • ​causes the cell to starve

  • ​more difficult to get waste OUT of the cell

    • ​causes the cell to become toxic

• ​More volume

  • ​cell needs more nutrients

  • ​cell produces more wastes

Multiple Select

Select all that apply: Why is a large SA:V better?

• More area to let in nutrients and release waste

• Processes occur more quickly

• Cell is more efficient

• Larger space for more storage of nutrients

Poll

Can a cell be too SMALL?

• Yes

• No

• Maybe

• Squirrel

​Cell Survival

​Cells need certain things to survive:

• ​nutrients (sugars, oxygen, water, etc.)

• ​organelles (mitochondria, ​Golgi apparatus, ​ER, ​Ribosomes, etc.)

Multiple Choice

Cells can’t be too small because . . .

• Need to hold parts necessary for function (ex. DNA and organelles)

• Need to be large enough to build an organism

• Can't function unless they are large

Multiple Select

What are some parts that cells need to function?

• Organelles

• DNA

• Nutrients (macromolecules)

​Large Cells DO Exist

​Some cells are relatively large compared to others:

• ​epithelial cells (skin cells)

• ​nerve cells

• ​muscle cells

• ​connective tissue cells

​

Large Cells

​Large cells maintain efficiency by:

• ​changing shape

• ​increase number of organelles

• ​increase number of nucleui

• ​modify structures

• ​increase amount of nutrients taken into the cell

• ​increase surface area using villi on cell surface (intestinal cells, lung cells), folding (Gogli apparatus, ER, mitochondria), or stacking (thylakoids)

• ​

Multiple Select

Cells that need to be larger for function can still maximize efficiency by:

• Changing shape/modifying structures

• Increasing number of organelles

• Increasing amount of nutrients

Multiple Select

One way to increase surface area in parts with larger volume is to....

• fold

• stack

• elongate/stretch

Multiple Choice

The mitochondria maximizes surface area by.....

• folding of inner membrane

• stacking

• increasing number of proteins

• reducing its size

Multiple Choice

SA is short for

• Surface area

• Volume

• Cell size

• Shape & area

Multiple Choice

V is short for

• Surface area

• Volume

• Varies

• Velicity

Multiple Select

Based on what you just learned about SA, V, and cell size: Why might elephants have ears that are very thin and elongated?

• Maximize surface area of very large animal to regulate body temperature

• Make it easier for them to hear clearly

• Way to attract mates

Multiple Select

Based on what you just learned about SA, V, and cell size: Why are lung cells very branched in structure?

• Maximize surface area for gas exchange to occur

• Reduce lung size and volume

• Prevent harmful materials from getting into lungs