Cell Structure

Question 1

What is the sequence of protein production?

Answer 1

1. Proteins made at ribosomes.
2. The ribosomes on the RER make proteins that are excreted/attached to the cell membrane.
3. New proteins produced at the Rough ER are folded and processed in the Rough ER.
4. Then they’re transported from the ER to the Golgi apparatus in the vesicles.
5. At the Golgi apparatus, the proteins may undergo further processing.
6. Proteins enter more vesicles to be transported around the cell.

Question 2

Structure of plasma.

Answer 2

-Found on surface of animal cells.
-Found inside cell wall of plant cells
-Made of lipids and proteins.

Question 3

Function of plasma.

Answer 3

-Regulates movement of substances into and out of the cell.
-Has receptor molecules on it, which allow it to respond to chemical like hormones.

Question 4

Structure of cell wall.

Answer 4

-Rigid structure that surrounds plant cells.
-Made if carbohydrate cellulose.

Question 5

Function of cell wall.

Answer 5

Supports plant cells.

Question 6

Structure of nucleus.

Answer 6

-Large organelle surrounded by a nuclear envelope (double membrane), contains many nucleolus.
-Contains chromatin and Structure called the nucleolus.

Question 7

Function of nucleus.

Answer 7

-Controls cells activities.
-DNS contains instructs to make proteins.
-Pores allow substances to move between nucleolus and the cytoplasm.
-Nucleolus makes ribosomes.

Question 8

Structure of lysosome.

Answer 8

-Round organelle surrounded by a membrane, with no clear internal structure.

Question 9

Function of lysosome.

Answer 9

-Contains digestive enzymes.
-These are kept separate from cytoplasm by surrounding membrane, and can be used to digest invading skin irritation to break down worn out components of cell.

Question 10

Structure of ribosome.

Answer 10

-Very small organelle that either floats free in the cytoplasm or is attached to the RER.
-Made up if proteins and RNA.
-Not surrounded by a membrane.

Question 11

Function of ribosome.

Answer 11

-Site where proteins are made.

Question 12

Structure of Rough Endoplasmic Reticulum.

Answer 12

-System of membranes enclosing a fluid-filled space.
-Surface is covered with ribosomes.

Question 13

Function of Rough Endoplasmic Reticulum.

Answer 13

-Folds and processed proteins that have been made at the ribosomes.

Question 14

Structure of Smooth Endoplasmic Reticulum.

Answer 14

-Similar to RER but with no ribosomes.

Question 15

Function of Smooth Endoplasmic Reticulum.

Answer 15

-Synthesises and processes lipids.

Question 16

Structure of Vesicle.

Answer 16

-Small fluid-filled sac in the cytoplasm, surrounded by a membrane.

Question 17

Function of Vesicle.

Answer 17

-Transports substances in and out of the cell.
-Some are formed by the Golgi apparatus or the Endoplasmic reticulum, while others are formed at the cell surface.

Question 18

Structure of Golgi apparatus.

Answer 18

-A group of fluid-filled membrane-bound, flattened sacs.
- Vesicles are often seen at the edges of the sacs.

Question 19

Function of Golgi apparatus.

Answer 19

-Processes and packages new lipids and proteins.
-It also makes lysosomes.

Question 20

Structure of Mitochondrion.

Answer 20

-Often oval-shaped.
-Double membrane.
-Inner folded to form structures called cristae.
-Inside is the matrix, which contains enzymes involved in respiration.

Question 21

Function of mitochondrion.

Answer 21

-Site of aerobic respiration where ATP is produced.
-Found in large numbers in cells that are very active and require a lot of energy.

Question 22

Structure of chloroplast.

Answer 22

-Small, flattened structure found in plant cells.
-Surrounded by a double membrane.
-Has membranes inside called thylakoid membranes.
-These membranes are stacked up in some grana.
-Grana are linked together by lamellae-thin flat pieces of thylakoid membranes.

Question 23

Function of chloroplast.

Answer 23

-Site where photosynthesis takes place.
-Some parts of photosynthesis happen in the grana, and other parts happen in the stroma.
-Stroma is a thick fluid found in chloroplast.

Question 24

Structure of centriole.

Answer 24

-Small, hollow cylinders.
-Made of microtubules.
-Found in animal cells, but only some plant cells.

Question 25

Function of centriole.

Answer 25

-Involved with the separation of chromosomes during cell division.

Question 26

Structure of cilia.

Answer 26

-Small, hair-like structures found on the surface membrane of some animal cells. -In cross-section, they have outer membrane a ring of 9 pairs of proteins microtubules inside, with two microtubules in the middle.

Question 27

Function of cilia.

Answer 27

-Microtubules allow the cilia to move. -This movement is used by the cell to move substances along the cell surface.

Question 28

Structure of flagellum.

Answer 28

-Flagella in eukaryotic cells are like cilia but longer. -They stick out from the cell surface. -Surrounded by the plasma membrane. -Inside they’re like cilia too - 2 microtubules in the centre and 9 pairs around the edge.

Question 29

Function of flagellum.

Answer 29

-Microtubules contract to make the flagellum move. -Flagellum are use like outboard motors to propel cell forward (similar to sperm cells).

Question 30

Functions of Cytoskeleton

Answer 30

-Microtubules and microfilaments support the cells organelles, keeping them in position. -Help to strengthen the cell and maintain its shape. -Responsible for the movement of materials within the cell. -Proteins in the cytoskeleton can also cause the cells to move.

Question 31

Prokaryotic cell.

Answer 31

-Small cells (less than 2 micro meters in diameter). -DNA is circular. -No nucleus. -Cell wall made of polysaccharide. -Few organelles and no mitochondria present and no membrane-bound organelles. -Flagella present. -Small ribosomes. -Example - E.coil bacterium.

Question 32

Eukaryotic cell.

Answer 32

-Larger cells (about 10-100 micro meters in diameter). -DNA is linear. -Nucleus present. -No cell wall. -Many organelles, mitochondria present and other membrane-bound organelles present. -Flagella present. -Larger ribosomes. -Example - Human liver cell.

Question 33

An unidentified cell is found to contain mitochondria. Is it prokaryotic or eukaryotic?

Answer 33

Eukaryotic because prokaryotic cells don’t contain mitochondria.

Question 34

Formula for magnification?

Answer 34

M=I/A

Question 35

Name the 3 types of microscopes.

Answer 35

-Light microscope. -Laser scanning confocal microscope. -Electron microscope.

Question 36

Um -> mm

Answer 36

/1000

Question 37

mm -> um

Answer 37

X1000

Question 38

Why do you need to stain a sample under a microscope?

Answer 38

The beam of light passes though the object being viewed. Sometimes an object is completely transparent. So staining an object makes sure that you can see the sample and it’s parts show up under the microscope.

Question 39

How to use a light microscope?

Answer 39

1. Start by clipping the slide containing the specimen you want to look at onto the stage. 2. Select the lowest-powered objective lens. 3. Use the coarse adjustment knob to bring the stage up to just below the objective lens. 4. Look down the eyepiece and use the coarse adjustment knob to move the stage downwards away from the objective lens until the image is roughly in focus. 5. Adjust the focus with the fine adjustment knob, until you get a clear image of what’s on the slide. 6. If you need to see the slide with greater magnification, swap to a higher-powered objective lens and refocus.

Question 40

How do you prepare a microscope slide?

Answer 40

1. Pipette a small drop of water onto the slide. 2. Then use tweezers to place your specimen on top of the water drop. 3. To put the cover slip on, stand the slip upright on the stage, next the the water droplet. Then carefully tilt and lower it so it covers the sample. Try not the get any air bubbles as they will obstruct your view of the specimen. 4. Once the cover slip is in position, add a stain to the sample. Do this carefully by putting a bit of paper towel next the the opposite edge and place a drop of stain next to the other edge if the slide. 5. The stain will get drawn under the slip, across the specimen and the excess will get soaked up by the paper towel. 6. Look ugh the eyepiece at your stained sample.