2A - Eukaryotic cells and organelles

Question 1

What are example of eukaryotic cells?

Answer 1

Animal cells, plant cells, algae and fungi.

Question 2

What are example of prokaryotic cells?

Answer 2

Bacteria.

Question 3

What are the 11 parts of an animal cell?

Answer 3

Plasma membrane
RER
nucleolus
nucleus
SER
lysosome
ribosome
nuclear envelope
golgi apparatus
cytoplasm
mitochondrion

Question 4

What are the 13 parts of a plant cell?

Answer 4

Plasma membrane
RER
nucleolus
nucleus
SER
lysosome
ribosome
nuclear envelope
golgi apparatus
cytoplasm
mitochondrion
cell wall (with plasmodesma)
vacuole
chloroplast

Question 5

Which cell are algae like?

Answer 5

Plant cells.

Question 6

What cell are fungal cells like and what is different about them?

Answer 6

Plant cells.

Their cell walls are made of chitin and they don’t have chloroplasts because they don’t photosynthesise.

Question 7

What is the cell-surface (plasma) membrane? What is it made of?

Answer 7

The membrane found on the surface of animal cells and just inside the cell wall of other cells. It’s made mainly of lipids and proteins.

Question 8

What is the function of the cell-surface (plasma) membrane?

Answer 8

Regulates the movement of substances into and out of the cell. It also has receptor molecules on it, which allow it to respond to chemicals like hormones.

Question 9

What is the nucleus? What does it contain?

Answer 9

A large organelle surrounded by a nuclear envelope (double membrane), which contains many pores. The nucleus contains chromosomes (which are made from protein-bound linear DNA. It also contains one or more structures called a nucleolus.

Question 10

What is the function of the nucleus?

Answer 10

Controls the cell’s activities (by controlling the transcription of DNA. DNA contains instructions to make proteins. The pores allow substances (e.g. RNA) to move between the nucleus and the cytoplasm. The nucleolus makes ribosomes.

Question 11

What does the nuclear envelope do?

Answer 11

Surrounds the nucleus and encases the genetic information. It is 2 lipid bilayer membranes.

Question 12

What do the nuclear pores do?

Answer 12

Used in the transport of molecules across the nuclear envelope. Includes RNA moving from the nucleus and proteins moving to the nucleus.

Question 13

What does the nucleoplasm do?

Answer 13

It is the substance of a cell’s nucleus and includes the chromosomes and the nucleolus.

Question 14

What do chromosomes do?

Answer 14

Made up of nucleic acid and proteins. Carry genetic information in the form of genes.

Question 15

What does the nucleolus do?

Answer 15

It is the largest structure in the nucleus and it makes ribosomes.

Question 16

What are mitochondria?

Answer 16

Usually oval-shaped. They have a double membrane - the inner one folded to form structures called cristae. Inside is the matrix, which contains enzymes involved in respiration.

Question 17

What is the function of the mitochondria?

Answer 17

The site of aerobic respiration, where ATP is produced. They’re found in large numbers in cells that are very active and require a lot of energy.

Question 18

What is the function of the mitochondria’s double membrane?

Answer 18

Outer membrane covers like a skin. Inner membrane folded into layered structures. Inner membrane increases surface area.

Question 19

What is the function of the mitochondria’s cristae?

Answer 19

Folds made by inner membrane mean that there is more space for chemical reactions to take place.

Question 20

What is the function of the mitochondria’s matrix?

Answer 20

Fluid contained within mitochondria. Has its own ribosomes and DNA floating in it. Contains granules which help with ion concentrations.

Question 21

What is a chloroplast?

Answer 21

A small flattened structure found in plant and algae cells. It’s surrounded by a double membrane, and also has membranes inside called thylakoid membranes. These membranes are stacked up in some parts of the chloroplast to form grana. Grana are linked together by lamellae - thin, flat pieces of thylakoid membrane.

Question 22

What is the chloroplast envelope?

Answer 22

Similar to the structure of the mitochondrial double membrane - (Outer membrane covers like a skin. Inner membrane folded into layered structures. Inner membrane increases surface area.)

Question 23

What are grana?

Answer 23

Stacks of discs called thylakoids which resembles a stack of coins.
Site of light-dependent reactions of photosynthesis.
Connected by intergranal thylakoids.

Question 24

What is the stroma?

Answer 24

Colourless fluid surrounding grana.
Contains enzymes required for photosynthesis.
DNA and ribosomes also present.

Question 25

What is the endoplasmic reticulum?

Answer 25

A system of membranes enclosing a fluid-filled space.

RER - has ribosomes attached to it so folds and processes proteins that have been made at the ribosomes.

SER - where lipids are synthesised and processed.

Question 26

What is the Golgi apparatus?

Answer 26

A group of fluid-filled, membrane-bound flattened sacs. Vesicles are often seen at the edges of the sacs. It processes and packages new lipids and proteins. It also makes lysosomes.

Question 27

What are lysosomes?

Answer 27

A round organelle surrounded by a membrane, with no clear internal structure. It’s a type of golgi vesicle.

They destroy unwanted parts in the cell.
Made in Golgi apparatus.
Contains strong digestive enzymes called lysozymes.

Question 28

What are the levels of organisation?

Answer 28

specialised cell
tissue
organ
organ system
organism

Question 29

What are the functions of golgi apparatus?

Answer 29

• Add carbohydrates to proteins to form glycoproteins.
• Produce secretory enzymes, such as those secreted by the pancreas.
• Secrete carbohydrates, such as those used in making cell walls in plants.
• Transport, modify and store lipids.
• Form lysosomes.

Question 30

When are lysosomes formed?

Answer 30

When the vesicles produced by the golgi apparatus contain enzymes such as proteases and lipases.

Question 31

What are the functions of lysosomes?

Answer 31

• Hydrolyse material digested by phagocytic cells such as white blood cells and bacteria.
• Release enzymes to the outside of the cell (exocytosis) in order to destroy material around the cell.
• Digest worn out organelles so that the useful chemicals they are made of can be re-used.
• Completely break down cells after they have died (autolysis).

Question 32

What are golgi vesicles?

Answer 32

A small fluid-filled sac in the cytoplasm, surrounded by a membrane and produced by the golgi apparatus. Stores lipids and proteins made by the golgi apparatus and transports them out of the cell (via the cell-surface membrane).

Question 33

What are ribosomes?

Answer 33

A very small organelle that either floats free in the cytoplasm or is attached to the RER. It is made up of proteins and RNA. It is not surrounded by a membrane.

The site where proteins are made. Can be 80s or 70s.

Question 34

What is the cell wall?

Answer 34

A rigid structure that surrounds cells in plants, algae and fungi. In plants and algae it’s made of cellulose and in fungi it is made of chitin.

It supports the cells and prevents them from changing shape.

Question 35

What is the cell vacuole?

Answer 35

A membrane-bound organelle found in the cytoplasm of plant cells. It contains cell sap which is a weak solution of sugar and salts. The surrounding membrane is called the tonoplast.

It helps to maintain pressure inside the cell and keeps the cell rigid. This stops plants wilting. Also involved in the isolation of unwanted chemicals inside the cell.

Question 36

What are epithelial cells in the small intestine specialised for and how are they adapted for this?

Answer 36

To absorb food efficiently.

• Villi on the walls of the intestine to increase surface area.
• Epithelial cells on the surface of the villi have folds in their cell-surface membranes, called microvilli which increase the surface area even more.
• They have lots of mitochondria to provide energy for the transport of digested food molecules into the cell.