Benchmark #2 Review

What is the difference between a prokaryotic cell and a eukaryotic cell?

Prokaryotes

- no organelles

- no nucleus

- most unicellular

organisms

- cell can only

carry out one

function at a time

Eukaryotes

- organelles

- nucleus

- most multicellular

organisms

- different parts of

the cell can

perform different

functions

What is the function of the nucleus?

The nucleus is the storehouse for most of

DNA, in your cells. DNA gives directions to

make proteins.

There are two major demands on the nucleus:

1. DNA must be carefully protected

2. DNA must be available for use at the

proper times.

\***The special

structure of the

nucleus helps

meet these demands.

What is the function of the golgi apparatus?

Consists of closely layered stack of

membrane-enclosed spaces that

process, sort, package and deliver

proteins.

What is the function of the ribosomes?

Sites where cell assembles enzymes &

other protein according to DNA

Not bound by a membrane within a cell

Move out of nucleus & into cytoplasm

in order to make proteins

Genetic blueprints in DNA must be

copied to RNA & sent to cytoplasm

through the nuclear pores

What is the function of the endoplasmic reticulum?

site of cellular reactions

Series of highly folded membranes

Rough ER - carry out function of protein

synthesis

Ribosomes attach to areas on Rough ER

Smooth ER - involved in biochemical activities

like production & storage of lipids

Ribosomes attach to areas on Rough ER

What is the function of the cell membrane?

is the boundary between

the cell & its environment

Its job is to allow a steady supply of

nutrients to come into the cell no matter

what the external condition are.

Removes excess of nutrients

Removes wastes & other products

Maintains homeostasis- process of

maintaining cell's environment

It is Selective permeability

Describe the following properties of water: Water has a high specific heat, Water is expands when it freezes, and Water is polar.

Water Has a High specific heat \= Because of all the H bonds water can

resist temperature change

• When conditions fluctuate it requires

more heat to increase its temperature

than do most liquids

• This is an important trait that helps

maintain homeostasis in cells

Water expands when it freezes \= Water is one of the few substances that

expands when it freezes

• Because of this property, ice is less dense

than liquid water so it floats as it forms in

a body of water.

Water is Polar \= A polar molecule is a molecule with an

unequal distribution of charge

This occurs when atoms in a covalent

bond do not share the e equally

Water has a + charge at the end of H

end and a - charge at the O end

This allows it to form H bonds between

molecules.

How does water help aid in the transport of proteins?

It helps move things around.

How does water flow through a semi permeable membrane?

When there are is a high concentration of

dissolved particles then the lower the

concentration of water.

A solution can be described as isotonic,

hypotonic, or hypertonic relative to another

solution.

Define passive transport.

is the movement of

molecules across the membrane from

areas of high concentration to areas of

low concentration. It does not require

energy input from the cell.

What are some examples of passive transport?

Diffusion and Facilitated Diffusion.

Define active transport.

drives molecules

across a membrane from a region of

lower concentration to a region f higher

concentration. (Against the concentration

gradient.)

Cell must expend energy to counter act