cell structure and function

Question 1

Describe the fluid mosaic model

Answer 1

one way to understand biological membranes. The components of the membrane form a mobile mosaic in the fluid-like environment created by a sea of phospholipids

Question 2

Cell theory states …

Answer 2

all organisms are made of cells
cells are the basic unit of life
cells come from other cells

Question 3

What structures make up the cell membrane?

Answer 3

phospholipid bilayer
protein channels
carbohydrate chain receptors

Question 4

What is diffusion?

Answer 4

The movement of liquid or gas particles from areas of high concentration to areas of lower concentration until equally distributed.

Question 5

What is osmosis?

Answer 5

The movement of water across the cell membrane from an area of low solute concentration to an area of high solute concentration until both regions have an equal concentration

Question 6

What is the purpose of the cell membrane?

Answer 6

To enclose the contents of the cell and manage the entry and exit of substances into and out of the cell.

Question 7

What does it mean to be semi-permeable?

Answer 7

Allows or prevents some substances from passing through.

Question 8

What happens during active transport?

Answer 8

Energy is used to move substances against the concentration gradient.

Question 9

What is homeostasis?

Answer 9

An organisms process of maintaining a stable internal environment suitable for sustaining life.

Question 10

How does the concentration gradient affect diffusion?

Answer 10

The rate of diffusion is faster when the difference between the higher and lower concentrations is greater.

Question 11

What are examples of passive transport?

Answer 11

Diffusion, osmosis, filtration

Question 12

What happens to a cell in a hypertonic solution?

Answer 12

Water leaves the cell so it shrivels - plasmolysis

Question 13

What happens in a hypotonic solution?

Answer 13

Water enters the cell so it swells - cytolysis

Question 14

How does surface area to volume ration affect osmosis?

Answer 14

The greater the SA:V the faster the rate of diffusion. (cells at ideal size to maintain rate)

Question 15

What is endocytosis?

Answer 15

A form of active transport where the cell membrane engulfs a particle from outside the cell and releases it into the cell.

Question 16

What is exocytosis?

Answer 16

A form of active transport where the cell membrane engulfs a particle inside a cell and releases it outside the cell.

Question 17

What happens to a cell in an isotonic solution?

Answer 17

It remains the same volume.

Question 18

What is a eukaryotic cell?

Answer 18

A complex cell containing membrane bound organelles. (eg nucleus, mitochondria, ribosomes)

Question 19

What is a prokaryotic cell?

Answer 19

A simple cell that has no membrane organelles. (eg DNA floats in the cytoplasm)

Question 20

Compare diffusion and osmosis

Answer 20

Osmosis is a form of diffusion limited to the passive transport of water through the cell membrane from a region of higher water to lower water concentration until the concentration is the same in both regions. Diffusion is the term used to describe the movement of gases or liquids from an area of higher to lower concentration until equally distributed.