Question

i. limits to cell growth
a. why do cells divide? instead of dividing, why dont cells just grow larger and larger?
there are two main reasons why type here rather than continuing to grow
:

1. the larger a cell becomes, the more
2. if the cell grows too large, it will have trouble moving enough

b. problem #1: our dna has its limits!

1. all of the that a cell needs to function is stored in the of the cell.
2. dna is packaged into. a chromosome consists of one very long

Explanation:

For part A:

• The first blank in the main sentence: Cells divide rather than just growing larger. So "cells divide" fits.
• The second blank: The context is about cells not just growing larger, so "larger" (completing "continuing to grow larger").
• Reason 1: As a cell becomes larger, the more demands it places on its DNA (or the more it needs for its functions, but the key concept here is the demand on DNA and the surface area - volume ratio related to material transport). So a common answer is "demands it places on its DNA" (or related to surface area to volume ratio, but the first main reason is often about DNA overload).
• Reason 2: If a cell grows too large, it has trouble moving enough nutrients and wastes across the cell membrane. So the blank would be "nutrients and wastes across the cell membrane".

For part B:

• Problem #1, 1st blank: All of the "information" (since DNA stores genetic information) that a cell needs to function is stored in the "nucleus" of the cell.
• Problem #1, 2nd blank: DNA is packaged into "chromosomes".

Answer:

Part A

• Main sentence blanks:
• First: cells divide
• Second: larger
• Reason 1: demands it places on its DNA
• Reason 2: nutrients and wastes across the cell membrane

Part B

• Problem #1, 1st:
• First blank: information
• Second blank: nucleus
• Problem #1, 2nd: chromosomes