Life on This Rock: Section 2 -3

Question 1

What is the nucleus?

Answer 1

A membrane enclosed area within the cell that houses the cell’s DNA.

Question 2

True or false? DNA never leaves the nucleus.

Answer 2

True.

Question 3

Although DNA never leaves the nucleus, what sometimes happens to the DNA?

Answer 3

Copies are made of portions of it.

Question 4

Why does DNA never leave the nucleus?

Answer 4

So that DNA can be protected and preserved.

Question 5

What are the nucleus’ copies of DNA made of?

Answer 5

RNA (Ribonucleic acid)

Question 6

Why is RNA much shorter than DNA?

Answer 6

Because it is a copy of only a particular section.

Question 7

Where do RNA messages leave the cell?

Answer 7

Through nuclear pores.

Question 8

What are nuclear pores?

Answer 8

Donut-shaped transmembrane proteins in the cell’s plasma membrane.

Question 9

What is the endoplasmic reticulum?

Answer 9

A branching, interconnecting series of tubes that go throughout the membrane of the nucleus.

Question 10

Where does the endoplasmic reticulum spread out to after it leaves the nuclear membrane?

Answer 10

The cytoplasm.

Question 11

What is the first portion of the endoplasmic reticulum covered by on the outside?

Answer 11

Ribosomes.

Question 12

What is the term for the first portion of the endoplasmic reticulum?

Answer 12

Rough endoplasmic reticulum.

Question 13

What marks the transition into the second part of the endoplasmic reticulum and what is this portion called?

Answer 13

The disappearance of ribosomes and it is called the smooth endoplasmic reticulum.

Question 14

What are ribosomes?

Answer 14

Little factories that assemble proteins from their amino acid monomers.

Question 15

What carries the code that allows a ribosome to assemble a protein?

Answer 15

The RNA message that left the nucleus.

Question 16

How does an RNA message reach the nucleus?

Answer 16

It moves through a channel in the center of the ribosome.

Question 17

What happens once an RNA message reaches the center of a ribosome?

Answer 17

The proper amino acids are brought together and assembled into a protein.

Question 18

True or false? All of the cell’s ribosomes are on the rough endoplasmic reticulum.

Answer 18

False. Some are floating free in the cytoplasm.

Question 19

Why do some ribosomes float free in the cytoplasm?

Answer 19

To allow certain proteins to remain in the cytoplasm and other to be sent along the passageway of the endoplasmic reticulum to the golgi apparatus.

Question 20

What is the golgi apparatus and what is it shaped like?

Answer 20

It is an area where different proteins gather to be modified and transported to different areas of the cell and it is shaped like a stack of pancakes.

Question 21

What are lysosomes?

Answer 21

They are the waste disposal units of the cell and recyclers.

Question 22

How do lysosomes destroy waste?

Answer 22

They have a very high or very low level of pH and special enzymes.

Question 23

What do lysosomes do with incoming vesicles containing food particles?

Answer 23

They break down the particles into amino acids and other monomers to be used by the cell to build things.

Question 24

How do lysosomes recycle old organelles?

Answer 24

They break down the old organelles into monomers the cell can use.

Question 25

Where do the destructive enzymes within lysosomes come from?

Answer 25

The Golgi apparatus.

Question 26

What would happen if the lysosome enzymes were not contained within the Golgi apparatus?

Answer 26

They would degrade everything they encountered and eventually destroy the cell.

Question 27

What is the purpose of mitochondria?

Answer 27

They create energy for the cell.

Question 28

Where do cells begin to break down sugars?

Answer 28

Within the cytoplasm.

Question 29

Where are the products of a cell's breakdown sent?

Answer 29

The mitochondria.

Question 30

What do the mitochondria do with the products of the cell's breakdown?

Answer 30

They break them down completely.

Question 31

How do mitochondria capture and store energy?

Answer 31

Through a series of reactions.

Question 32

How many membranes do mitochondria have and why?

Answer 32

Two, so that they may organize the steps of the reactions that allow them to store energy.

Question 33

What do mitochondria use to power their reactions?

Answer 33

Oxygen.

Question 34

What do mitochondria create as a waste product?

Answer 34

Carbon dioxide.

Question 35

What does the extracellular matrix allow animal cells to do?

Answer 35

Form tissues and organs.

Question 36

What is a desmosome?

Answer 36

A structure formed by the transmembrane proteins holding each other together.

Question 37

What is the extracellular matrix?

Answer 37

A complex array of fibers and proteins that bind cells together.

Question 38

What does the extracellular matrix assemble from?

Answer 38

Proteins secreted from the cells themselves.

Question 39

What is collagen?

Answer 39

The material that helps to make cartilage and bone.

Question 40

True or false? Collagen is not one of the proteins that makes up the extracellular matrix.

Answer 40

False.

Question 41

What is the extracellular matrix used for in stem cell therapy?

Answer 41

It helps to coax stem cells into action.

Question 42

What are chloroplasts?

Answer 42

They are the energy factories of plant cells and algae.

Question 43

How do chloroplasts create energy for the cell?

Answer 43

They capture the sun's energy and use it to build sugars.

Question 44

Where do chloroplasts get the carbon they need to make sugars?

Answer 44

The carbon dioxide that plants take in from the atmosphere.

Question 45

What happens to the oxygen from the carbon dioxide taken in by the plant?

Answer 45

It is ejected back into the atmosphere.

Question 46

What is the series of membranes within the outer membrane of a chloroplast used for?

Answer 46

The process of building sugars.

Question 47

True or false? Plant cells have lysosomes.

Answer 47

False.

Question 48

what do plant cells have that replace lysosomes?

Answer 48

A central vacuole.

Question 49

What is the purpose of the central vacuole?

Answer 49

They store water and pump in enzymes that degrade o;d molecules for recycling.

Question 50

What helps a plant cell to maintain its shape during periods of too little or too much water?

Answer 50

The cell wall.

Question 51

True or false? Animal cells do not have a cell wall.

Answer 51

True.

Question 52

What are bacteria?

Answer 52

Single-celled organisms with only one chromosome of DNA and no nucleus.

Question 53

How do bacteria reproduce?

Answer 53

Binary fission.

Question 54

What is binary fission?

Answer 54

When a single-celled organism splits into two halves and each half becomes a new organism.

Question 55

How often do bacteria reproduce?

Answer 55

At least every twenty minutes.

Question 56

True or false? Bacteria have a cell wall and ribosomes.

Answer 56

True.

Question 57

What do many bacteria use to propel themselves?

Answer 57

Flagellum.

Question 58

Are bacteria prokaryotes or eukaryotes?

Answer 58

Prokaryotes.

Question 59

Are animal and plant cells prokaryotes or eukaryotes?

Answer 59

Eukaryotes.

Question 60

What is the main difference between prokaryotes and eukaryotes?

Answer 60

Prokaryotes do not have membrane-bound organelles.

Question 61

Did prokaryotes or eukaryotes come first?

Answer 61

Prokaryotes.

Question 62

What is it thought that mitochondria may be the descendants of?

Answer 62

Bacteria that were engulfed by primitive eukaryotes.

Question 63

What are algae?

Answer 63

Single-celled prokaryotes that carry the machinery necessary for photosynthesis.

Question 64

What is the theory that mitochondria and chloroplasts evolved from engulfed prokaryotes called?

Answer 64

Endosymbiosis.

Question 65

What are some lines of evidence that support endosymbiosis?

Answer 65

Mitochondria and chloroplasts contain their own DNA that creates proteins for these organelles. We also cannot make more mitochondria or chloroplasts.

Question 66

What did the engulfed bacteria and algae gain from endosymbiosis?

Answer 66

Protection.

Question 67

What did the eukaryotes gain from endosymbiosis?

Answer 67

Nutrients.