Cell Growth and Division

Cell Growth + Division (part 1)

Limits to Cell Size

Chromosomes

The Cell Cycle

Learning Objectives

• Identify the problems growth causes for cells

• Explain the main events of each of the four phases of the cell cycle

THE LIMITS OF CELL SIZE

Why are cells so tiny?
Is there a limit on how big a cell gets?

1.Increased demand on DNA

2.Harder to move nutrients/waste in & out of cell

a.As cell grows, volume in cell increases
faster than surface area of cell membrane

b.As volume increases then there will be
more need for:

i.surface area as there’s more of a
need for “food” to enter

ii.waste to be excreted

iii.

more metabolic reactions occurring in
this larger volume to keep the cell
alive

The size of cells is limited by the distance

oxygen and nutrients can effectively

diffuse to provide the inside with enough
resources - life avoided this problem by

forming multicellular structures!

CELL GROWTH

Multicellular organisms grow in size and complexity due to cell growth + division

​

​Watch the short time lapse video clip to the right to observe cell division of a tadpole egg

​Watch the video on the next slide to learn about how big cells can get

Multiple Select

Why can't a single cell constantly get bigger and bigger forever? (select the four statements that apply)

• it would be difficult to get enough oxygen and nutrients in the cell

• would be harder to move materials around the inside of the cell

• too much stress on cell's DNA

• would be harder to get waste out of the cell

• the surface area to volume ratio would always be the same

Knowledge Checkpoint!

3 Questions

Multiple Choice

During cell division DNA is wrapped around special proteins and condensed, when it is like this it is called a

• centromere

• nucleus

• chromosome

• histone

Multiple Choice

All organisms have the same amount of DNA and chromosomes

• True

• False

Multiple Choice

When chromosomes replicate and you see an X shape, the X contains

• 2 sister chromatids

• 1 daughter chromatid

• 1 parent chromatid

THE CELL CYCLE

How cells grow

Cell Cycle

• ​G1 = Cell Growth

• ​S = DNA replication (have 2 sets of DNA)

• ​G2 = more growth

• ​M = Mitosis + Cytokinesis

Knowledge Checkpoint!

7 Questions

Multiple Choice

What is the proper sequence of the Cell Cycle?

• M, G₂, S, G₁

• G₁, G₂, S, M

• G₁, S, G₂, M

Multiple Select

Which 3 phases of the Cell Cycle make up Interphase?

• G₁ phase

• S phase

• G₂ phase

• M phase

Multiple Choice

Which phase of the Cell Cycle involves cell growth and synthesis of new proteins and organelles?

• G₁

• S

• G₂

• M

Multiple Choice

Which phase of the Cell Cycle involves DNA replication?

• G₁

• S

• G₂

• M

Multiple Choice

Which phase of the Cell Cycle involves cell growth and many of the organelles and molecules required for cell division are produced?

• G₁

• S

• G₂

• M

Multiple Choice

Which phase of the Cell Cycle involves cell division (mitosis + cytokinesis)

• G₁

• S

• G₂

• M

Multiple Choice

Which part of the Cell Cycle normally takes place quickly?

• interphase

• cell division

​You completed this lesson!