The Internal Environment of Organisms

Question 1

What is homeostasis?

Answer 1

a condition of balance in your body that happens automatically to create and maintain an environment for your brain to function

Question 2

Do all living organisms have homeostasis?

Answer 2

Yes, all living organisms have homeostasis. It is a fundamental characteristic of all living systems.

Question 3

In animals, what helps to maintain homeostasis?

Answer 3

internal organs that are similar in function to those in humans help to maintain homeostasis

Question 4

In amoebas, how do they remove waste?

Answer 4

the removal of toxic waste happens without complicated internal organs and with few specialized structures

Question 5

What can losing homeostasis for an extended period of time mean to an organism?

Answer 5

Death

Question 6

What is needs to maintain homeostasis? Explain both mechanisms

Answer 6

• organism must be able to sense when changes have taken place in the external and internal environment
• it must be able to respond with appropriate adjustments

Question 7

Explain each step of what happens to the human body when it senses cold

Answer 7

Humans can monitor stimuli, or external signals such as cold, because we have sensory neurons in our skin that allows us to feel the outside temperature. Once the message “cold” is received in the brain, our body can respond by changing blood flow. Our heart rate may increase. Certain blood vessels may constrict. This change is involuntary or automatic.

Question 8

Are most homeostasis reactions voluntary or involuntary?

Answer 8

Involuntary

Question 9

What will the human body start to sacrifice to keep the organs balanced?

Answer 9

The body responds to cold temperatures by diverting circulation to keep the most important internal organs warm.

Question 10

What will the human body do if it senses that it is getting too hot?

Answer 10

The circulatory system diverts blood flow away from the internal organs. This protects them from damage caused by excess heat.

Question 11

Explain how guard cells control the rate of water loss in plants

Answer 11

Water loss is controlled by the condition of special cells, called guard cells. These cells regulate the size of microscopic pores in the leaves. These pores are called stomata’s. When the plant has sufficient water, the guard cells shrink. The stomata’s remain closed which preserves the water.

Question 12

What are the two major sections we divide the eukaryotic cell into?

Answer 12

Nucleus and cytoplasm

Question 13

What is the cytoplasm?

Answer 13

The portion of the cell outside the nucleus

Question 14

What does the nucleus contain?

Answer 14

Nearly all the cell’s DNA and with it the coded instructions for making proteins and important molecules.

Question 15

What is chromatin? What does it form when a cell divides?

Answer 15

The granular material you can see in the nucleus is called chromatin. Chromatin consists of DNA bound to protein. When a cell divides, chromatin condenses to form chromosomes

Question 16

What does the chromosome contain?

Answer 16

The genetic information that is passed from one generation of cells to the next

Question 17

What do ribosomes do? What are they?

Answer 17

Small particles or RNA and protein found throughout the cytoplasm. They produce proteins by following coded instructions that come from the nucleus.

Question 18

What is the endoplasmic reticulum the site of?

Answer 18

The site where lipid components of the cell membrane are assembled along with proteins and other materials that are exported from the cell

Question 19

What does the rough ER do?

Answer 19

Newly made proteins leave these ribosomes and are inserted into the rough ER, where they may be chemically modified

Question 20

What does the smooth ER do?

Answer 20

Contains collections of enzymes that perform specialized tasks, including the synthesis of membrane lipids and the detoxifying of drugs.

Question 21

Into what organelle, do the proteins produced in the rough ER go to next?

Answer 21

The liver cells

Question 22

What is the function of the Golgi Apparatus? What does it look like?

Answer 22

The function of the Golgi Apparatus is to modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell

Question 23

What are lysosomes? What is one function of the lysosomes?

Answer 23

Lysosomes are the small organelles filled with enzymes. One function of lysosomes is the digestion, or the breakdown of lipids, carbohydrates, and proteins into small molecules tat can be used by the rest of the cell.

Question 24

What can we trace back to lysosomes that fail?

Answer 24

A number of serious human diseases, including Tay-Sachs disease, can be traced to lysosomes that fail to function properly.

Question 25

What are vacuoles? What types of organisms have vacuoles?

Answer 25

Vacuoles are saclike structures that store materials such as water, salts, proteins, and carbohydrates. Vacuoles are found in some single structured organisms, plants, and animals.

Question 26

What are mitochondria? What types of organisms have mitochondria?

Answer 26

Mitochondria are organelles that convert the chemical energy stored in food into compounds that are more convent for the cells to use.
Nearly all eukaryotic cells, including plants, contain mitochondria.

Question 27

Where do humans inherit their mitochondria from?

Answer 27

Nearly all of our mitochondria comes from the cytoplasm of the ovum, or egg cell.

Question 28

What are chloroplasts? What organisms have these?

Answer 28

Chloroplasts are organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis.
Plants and some other organisms contain chloroplasts.

Question 29

What does the cytoskeleton do? What is it also involved in?

Answer 29

The cytoskeleton is a network of protein filaments that helps the cell to maintain its shape.
The cytoskeleton is also involved in movement.

Question 30

What are the microfilaments made of?

Answer 30

Microfilaments are threadlike structures made of a protein called actin. They form extensive networks in some cells and produce a tough, flexible network that supports the cell.

Question 31

What are centrioles? What organisms do not have them?

Answer 31

Centrioles are located near the nucleus and help organize cell division.
Centrioles are not found in plant cells.

Question 32

What is the cell membrane? What does it do?

Answer 32

The cell membrane regulates what enters and leaves the ell and also provides protection and support for the cell.

Question 33

What is the cell membrane made up of? What does this do for the cell?

Answer 33

Most cell membranes contain protein molecules that are embedded in the lipid bilayer. Some of the proteins form channels and pumps that help to move material across the cell membrane.

Question 34

What else does the cell membrane contain other than lipids?

Answer 34

Most cell membranes contain protein molecules that are embedded in the lipid bilayer.

Question 35

What organisms have cell walls? What is the main function?

Answer 35

The main function of the cell wall is to provide support and protection for the cell.
Cell walls are present in many organisms, including plants, algae, fungi, and many prokaryotes.

Question 36

What is a solution?

Answer 36

Uniform mixtures of two or more substances

Question 37

What is a solute?

Answer 37

The substances in a solution

Question 38

What is a solvent?

Answer 38

The substance that the solute is dissolved into

Question 39

Give an example of a solute and solvent

Answer 39

When salt dissolves in water, the salt is the solute and water is the solvent

Question 40

What does iso mean?

Answer 40

Equal

Question 41

What is an isotonic solution?

Answer 41

Provides an environment in which the concentration of solutes outside the cell equals the concentration of the solutes inside

Question 42

What does hyper mean?

Answer 42

Over

Question 43

Describe a hypertonic solution

Answer 43

The concentration of solutes outside a cell is greater than the concentration inside

Question 44

What does hypo mean?

Answer 44

Under

Question 45

Describe a hypotonic solution

Answer 45

The concentration of solutes outside the cell is less that the concentration inside