Eukaryotic organelles

Question 1

What is the plasma membrane?

Answer 1

The membrane found on the surface of animal cells and just inside the cell wall of plant cells and prokaryotic cells, made of lipids and proteins

Question 2

What is the function of the plasma membrane?

Answer 2

It regulates the movement of substances into and out of the cell and also has receptor molecules on it which allow it to respond to chemicals such as hormones

Question 3

What is the cell wall?

Answer 3

A rigid structure that surrounds the plant cell mainly made of cellulose

Question 4

What is the function of the cell wall?

Answer 4

To support the plant cell

Question 5

What is the the nucleus?

Answer 5

A large organelles surrounded by the nuclear envelope (double membrane) which contains pores. The nucleus also contains chromatin (made of DNA and proteins) and also the nucleolus

Question 6

What is the function of the nucleus?

Answer 6

It controls the cell’s activities (by controlling the transcription of DNA) and DNA which contains instructions to make proteins. The pores allow substances, such as RNA, to move between the nucleus and the cytoplasm and the nucleolus makes ribosomes.

Question 7

What is a lysosome?

Answer 7

A round organelle surrounded by a membrane with no clear internal structure.

Question 8

What is the function of the lysosome?

Answer 8

It contains digestive enzymes which are kept separate from the cytoplasm by the surrounding membrane. They can be used to digest invading cells or break down worn out components of the cell.

Question 9

What is the ribosome?

Answer 9

A very small organelle (80S in a eukaryotic cell) which either floats free in the cytoplasm or is attached to the RER. It is made up of proteins and RNA but is not surrounded by a membrane.

Question 10

What is the function of the ribosome?

Answer 10

It is the site where proteins are made

Question 11

What is the rough endoplasmic reticulum?

Answer 11

A system of membrane that enclose a fluid filled space and the surface is covered with ribosomes.

Question 12

What is the function of the rough endoplasmic reticulum?

Answer 12

It folds and processes proteins that have been made at the ribosomes

Question 13

What is the smooth endoplasmic reticulum?

Answer 13

A system of membranes enclosing a fluid filled space (looks more bubbly and less distinctive layers)

Question 14

What is the function of the smooth endoplasmic reticulum?

Answer 14

It synthesises and processes lipids.

Question 15

What is a vesicle?

Answer 15

A small fluid filled sac in the cytoplasm surrounded by a membrane.

Question 16

What is the function of the vesicle?

Answer 16

Transports substances in and out of the cell (via the plasma membrane) and between organelles (transport vesicle). Some are made at the golgi apparatus or the endoplasmic reticulum , while some are formed at the cells surface (secretory vesicle)

Question 17

What is the golgi apparatus?

Answer 17

A group of fluid filled, membrane bound, flattened sacs and vesicles are often seen at the edge (looks like a fingerprint as more stacked, distinct layers)

Question 18

What is the function of the golgi apparatus?

Answer 18

It processes and packages new lipids and proteins and also makes lysosomes.

Question 19

What is the mitochondrion?

Answer 19

An oval shaped organelle which is double membranes and the inner one is folded to form structures call cristae. Inside there is matrix which contains enzymes involved in respiration.

Question 20

What is the function of a mitochondrion?

Answer 20

It is the site of aerobic respiration and where ATP is produced so they also found is very large numbers in cells that are very active and require lots of energy.

Question 21

What is a chloroplast?

Answer 21

A small flattened structure found only in plant cells and is surrounded by. double membrane and also has membranes inside called thylakoid membranes. The thylakoid membranes are stacked in some parts to form grana which are linked together by lamellae which are thin flat pieces of thylakoid membrane. It also contains a thick fluid within itself called stroma.

Question 22

What is the function of a chloroplast?

Answer 22

The site where photosynthesis takes place. Some parts of photosynthesis happen until he grana and some is the stroma.

Question 23

What is a centriole?

Answer 23

A small hollow cylinder made of microtubules (tiny protein cylinders) and is found in animal cells but only some plant cells.

Question 24

What is the function of a centriole?

Answer 24

It is involved in the separation of chromosomes during cell division

Question 25

What is cilia?

Answer 25

Small hair-like structure found in the surface membrane of some animal cells. In cross section, they have an outer membrane and a ring of 9 pairs of protein microtubules inside with two microtubules in the centre (this is known as the 9+2 formation)

Question 26

What is the function of cilia?

Answer 26

The microtubules allow the cilia to move and the movement is used by the cell to move substances along the cell surface

Question 27

What is the flagellum?

Answer 27

On eukaryotic cells, they are like cilia but longer and stick out from the cells surface and are surrounded by the plasma membrane. Inside, they also have the 9+2 structure

Question 28

What is the function of the flagellum?

Answer 28

The microtubules contract to make the flagellum move as the flagellum is used like outboard motors to propel cells forward (e.g, when a sperm cell swims)

Question 29

What is the plasmodesmata?

Answer 29

Channels within the cell wall and membrane of a plant cell

Question 30

What is the function of the plasmodesmata?

Answer 30

They are channels for exchanging substances with adjacent cells