Ch 3.4 Eukaryotic Cell Structure

Question 1

What is the structure of the plasma membrane?

Answer 1

Mainly composed of a phospholipid bilayer. It is embedded with peripheral and integral proteins. This plasma membrane also contains sterols (ex: cholesterol) and specialized lipids (ex: sphingolipids)

Question 2

What is the function of the plasma membrane?

Answer 2

They provide a cell with structural stability and protect it from harsh environments.

Question 3

What is the structure of the cell wall?

Answer 3

It is made up of many different types of material depending on the type of eukaryotic cells.

Question 4

What are the cell walls of plant cells made up of?

Answer 4

Cellulose

Question 5

What are the cell walls of protists and algae made up of?

Answer 5

biogenic silica, calcium carbonate, carrageenan, and agar

Question 6

What are the cell walls of fungi made up of?

Answer 6

Chitin

Question 7

What is the function of the cell wall?

Answer 7

They provide a cell with structural stability and protect it from harsh environments

Question 8

What is the structure of the glycocalyx/extracellular matrix?

Answer 8

Located in the spaces between adjacent cells, it is a sticky mass made up of carbohydrates and proteins. It is made up of proteoglycans that form the bulky mass and fibrous proteins that provide strength. They are attached to fibronectin which is also attached to integrin proteins.

Question 9

What are the functions of the glycocalyx/extracellular matrix?

Answer 9

It allows cells in tissues to hold out against external stresses. The extracellular matrix communicates signals from outside of the cell to the inside

Question 10

What is the structure of cilia?

Answer 10

Structures shorter than flagella that often cover the whole surface of the cell. It contains a 9+2 array of microtubules and a basal body at its end attaches it to the cell

Question 11

What is the function of cilia?

Answer 11

Its main function is motility; they also sweep particles past cells or into cells

Question 12

What is the structure of flagella?

Answer 12

They are flexible whips composed of a central pair of microtubules surrounded by nine parallel pairs of microtubules, 9+2 array

Question 13

What is the function of flagella?

Answer 13

locomotion; they help a cell move from one place to another

Question 14

What is the structure of cytoplasm?

Answer 14

A gel-like fluid inside the cell. It is mostly water with dissolved material that makes it viscous. It is found in all eukaryotic cells

Question 15

What is the function of the cytoplasm?

Answer 15

Supports the organelles and suspends them

Question 16

What is the structure of the nucleus?

Answer 16

A structure in all eukaryotes that is bound by a nuclear envelope that contains nuclear pores. The nuclear lamina determines the shape of the nucleus. Intermediate filaments outside the nucleus help keep the nucleus in position

Question 17

What is the function of the nucleus?

Answer 17

It regulates the activities of the cell as it contains the cell’s DNA

Question 18

What type of nucleic acid do eukaryotes have as their genome? How is it packaged?

Answer 18

DNA; it is arranged into linear chromosomes. It is wrapped around histones and condensed to fit inside the nucleus.

Question 19

What ribosomes are found in eukaryotic cells?

Answer 19

free ribosomes and membrane-bound ribosomes

Question 20

Free ribosomes vs. Membrane bound ribosomes

Answer 20

Free ribosomes are located in the cytoplasm of the cell while membrane-bound ribosomes are attached to the rough endoplasmic reticulum

Question 21

What is the size of ribosomes in eukaryotic cells?

Answer 21

80S ribosomes that have a 40S small subunit and a 60S large subunit

Question 22

What is the size of ribosomes in the eukaryotic cell organelles (chloroplasts and mitochondria)?

Answer 22

70S ribosomes like prokaryotes and have a 30S small subunit and a 50S large subunit

Question 23

Are ribosomes found in all eukaryotic cells?

Answer 23

Yes

Question 24

What is the function of the ribosome?

Answer 24

1) Free ribosomes are responsible for water-soluble protein synthesis
2) membrane-bound ribosomes serve to synthesize proteins that are destined for export out of the cell or for insertion into the cell membrane

Question 25

What type of ribosomes do eukaryotes have? What are the sizes of the large and small subunits?

Answer 25

non-organelle-associated ribosomes are 80S ribosomes. They have a 60S large subunit and a 40S small subunit. However, ribosomes that are in organelles like mitochondria and chloroplasts are 70S ribosomes. They are the same size as prokaryotic ribosomes with a 50S large subunit and a 30S small subunit

Question 26

What is the structure of the cytoskeleton?

Answer 26

It is a network inside all eukaryotic cells that is made up of microtubules, microfilaments, and intermediate filaments.

Question 27

What are the function of the cytoskeleton?

Answer 27

1) provides a network where things can be transported in the cell
2) Organelles can be anchored on this network and held in place.
3) helps maintain the structure of the cell.
4) allows the membrane to change shape and move around

Question 28

What is the endomembrane system?

Answer 28

This system in all eukaryotic cells is comprised of multiple organelles, which include the endoplasmic reticulum, Golgi apparatus, lysosomes, and vesicles. They are important for the movement of materials inside a cell and for the synthesis of cell components.

Question 29

What is the structure of the rough ER?

Answer 29

it is studded with ribosomes and is important in the production of proteins.

Question 30

What is the function of the rough ER?

Answer 30

After the ribosomes synthesize proteins, they are inserted into the rough endoplasmic reticulum’s membrane. There, the small sacs that contain the proteins bud off and are now transport vesicles. They either move to the Golgi apparatus, into the plasma membrane, or out of the cell.

Question 31

What is the function of smooth ER?

Answer 31

detoxifying toxic substances, carbohydrate metabolism, and the biosynthesis of lipids.

Question 32

What are the functions of the golgi apparatus?

Answer 32

Lipids and proteins get modified by enzymes in the Golgi. It functions in producing glycolipids, glycoproteins, or proteoglycans. Proteins get covalently modified, glycosylated, and sorted. Proteins can be transported to the plasma membrane or become lysosomes.

Question 33

What is the function of the lysosome?

Answer 33

contains digestive enzymes that are important in breaking down microorganisms, particles, cellular debris, and immune complexes. They break down things into their monomeric parts, it is the recycling center of the cell.

Question 34

What is the structure of mitochondria?

Answer 34

contains two lipid membranes, an inner and outer membrane. The inner membrane contains the mitochondrial matrix and is embedded with proteins. The mitochondrial matrix within the inner membrane has metabolic enzymes, 70S ribosomes, and mitochondrial DNA. Cristae, the invaginations of the inner membrane, increase the surface area of mitochondria. Not all eukaryotic cells have mitochondria.

Question 35

What is the function of mitochondria?

Answer 35

play an important role in aerobic cellular respiration.

Question 36

What is the structure of chloroplasts?

Answer 36

made up of an outer membrane, an inner membrane, and a thylakoid membrane system. Stroma, found inside the inner and outer membranes, is a gel like fluid that makes up a lot of the chloroplast’s volume. The thylakoid system floats around the stroma. This system is a collection of folded membrane sacs that are either arranged in stacks (grana) or free floating. These organelles are found only in plant and algal cells

Question 37

What is the function of chloroplasts?

Answer 37

where photosynthesis occurs in plant and algal cells