Topic 1 - Cell Structure

Question 1

Millimeters into Micrometers into Nanometers

Answer 1

1mm equal 1000μm, 1μm equals 1000Nm

Question 2

Equation for Calculating actual size of a specimen

Answer 2

Actual Size = Image Size/Magnification

Question 3

Define Magnification

Answer 3

The number of times an image is larger than the original

Question 4

Define Resolution

Answer 4

The smallest distance between 2 points where both points can still be distinguished

Question 5

What are the two types of microscopes?

Answer 5

Optical Microscopes (Light) and Electron Microscopes (SEM and TEM)

Question 6

Which kind of microscope has better resolution and why?

Answer 6

Electron Microscopes due to a electron having a shorter wavelength compared to light

Question 7

Structure of Nucleus:

Answer 7

Nucleus surrounded by nuclear envelope, a double membrane, nuclear pores enable movement of molecules into and out of nucleus. Genetic material is found within the nucleus. Nucleolus is a region within the nucleus that synthesizes ribosomes

Question 8

Roles of nucleus

Answer 8

To store the genetic material (DNA) of the cell. To synthesize ribosomes. To regulate production of messenger RNA for protein synthesis.

Question 9

What are the functions of the cell surface membrane

Answer 9

It encloses cell to form the boundary between the cytoplasm and the outside environment. To control the movement of substances in and out of the cell, as it is selectively permeable. Contains proteins and important molecules for cell signaling and recognition.

Question 10

How does the structure of the rough endoplasmic reticulum (RER) relate to its function?

Answer 10

The RER contains ribosomes on its surface for the synthesis of proteins. The RER membranes spread extensively throughout the cell for the transport of proteins.

Question 11

Difference between SER and RER

Answer 11

SER does not have ribosomes on the surface

Question 12

What is the function of the smooth endoplasmic reticulum (SER)?

Answer 12

SER synthesizes and transports lipids

Question 13

Structure of Mitochondria:

Answer 13

Oval-shaped. Double membrane bound, inner membrane folded into cristae. Contains jelly-like fluid called the matrix. Contains circular DNA and 70S ribosomes.

Question 14

Roles of Mitochondria:

Answer 14

Aerobic respiration, which produces ATP. The ATP is used for energy-requiring processes.

Question 15

Function of Golgi Body:

Answer 15

Modification and packaging of protein and lipids for exocytosis or distribution within the cell. It also produces lysosomes.

Question 16

What are lysosomes?

Answer 16

Vesicles from the Golgi body that contain digestive enzymes e.g. proteases, lipases and lysozymes.

Question 17

Function of lysosomes

Answer 17

They hydrolyze ingested pathogens in phagocytes. They digest old, worn out organelles in the cells. They break down cells after cell death.

Question 18

What are the two types of ribosomes and where are they found?

Answer 18

80S ribosomes are found in eukaryotic cells - in the cytoplasm and on the RER. 70S ribosomes are found in prokaryotic cells, chloroplasts and mitochondria.

Question 19

Structure of ribosomes:

Answer 19

Ribosomes contain two subunits. Each subunit is made up of a ribosomal RNA molecule and a protein.

Question 20

Function of ribosomes:

Answer 20

Protein synthesis

Question 21

Function of Centrioles and microtubules

Answer 21

Centrioles organize microtubules . Microtubules compose the cytoskeleton to give structure and allow transport within the cell.

Question 22

What is Cilia?

Answer 22

Cilia is a hair-like structure that projects from a cell. Cilia may be able to move (motile) or be stationary (non-motile).

Question 23

What is Microvilli?

Answer 23

Microvilli are small protrusions of the cell membrane.

Question 24

How does microvilli aid in exchange of substances in cells?

Answer 24

The microvilli increase the surface area of a cell to increase the efficiency of exchange. For example, the epithelial cells of the intestines have microvilli to absorb the products of digestion.

Question 25

Structure of Chloroplasts:

Answer 25

Chloroplasts have a double membrane and contain a fluid called stroma. Within the chloroplast, thylakoids are arranged into interconnected stacks of grana. They also contain 70S ribosomes and circular DNA.

Question 26

Name the photosynthetic pigment in chloroplasts.

Answer 26

Chlorophyll

Question 27

Function of Chloroplasts:

Answer 27

Photosynthesis, producing glucose, oxygen and some ATP

Question 28

Functions of Cell wall

Answer 28

Protects cellular contents and gives rigidity to plant structure. It protects the cell from osmotic lysis. It can regulate the movement of water.

Question 29

Function of Plasmodesmata

Answer 29

To allow the undisrupted flow of materials via the simplistic route, and the efficient exchange of substances between cells without having to cross the cell wall and membrane

Question 30

What is the name of the membrane surrounding the large vacuole

Answer 30

The tonoplast

Question 31

Function of vacuole

Answer 31

Acts as a temporary food store and helps maintain turgor pressure

Question 32

Name the organelles and cell structures that are present in plant cells, but not in animal cells.

Answer 32

A cell wall, chloroplasts, large vacuole and tonoplast, plasmodesmata

Question 33

Bacterial cells are what kinds of cells

Answer 33

Prokaryotic cells

Question 34

Differences between Prokaryotic and Eukaryotic cells

Answer 34

Prokaryotic - Small, no membrane bound organelles, circular DNA, 70s ribosomes, no ER

Eukaryotic - Large, organelles may feature no membrane, single membrane or double membrane, true nucleus, 80s ribosomes, has ER

Question 35

Key features of viruses

Answer 35

Viruses contain nucleic acids (either RNA or DNA) surrounded by a protein coat known as a capsid. The capsid can have attachment proteins to gain access to host cells. Viruses possess no organelles or ribosomes and so rely on host cells to synthesize the components of viral particles. Some viruses may have a phospholipid envelope surrounding the capsid e.g. HIV