3A

Question 1

Give three ways in which eukaryotes and prokaryotes differ

Answer 1

Prokaryotes have no membrane bound organelles, DNA is not bound within a nucleus, ribosomes are smaller

Question 2

How are multicellular organisms organised?

Answer 2

Cell - tissue- organ- organ system- organism

Question 3

Describe the structure of the nucleus

Answer 3

Structure = surrounded by a double membrane, with pores that allow molecules to enter and leave. Contains chromatin

Question 4

Describe the function of the nucleus.

Answer 4

Function = stores DNA, coordinates cell activities.

Question 5

Describe the structure of the rough endoplasmic reticulum.

Answer 5

Structure = a series of membranes enclosing a fluid filled space, with large numbers of ribosomes on the surface.

Question 6

Describe the structure of the smooth endoplasmic reticulum.

Answer 6

Structure = a series of membranes enclosing a fluid filled space, without ribosomes on the surface.

Question 7

Describe the function of the smooth endoplasmic reticulum.

Answer 7

Function = synthesises and processes lipids.

Question 8

Describe the structure of the Golgi apparatus.

Answer 8

Structure = flat, curved, fluid-filled sacs surrounded by vesicles.

Question 9

Describe the function of the Golgi apparatus.

Answer 9

Function = processes and packages proteins and lipids, produces lysosomes.

Question 10

Describe the structure of the mitochondria.

Answer 10

Structure = bound by a double outer membrane, inner membrane folded to increase surface area, folds = cristae, fluid is called matrix

Question 11

Describe the function of the mitochondria

Answer 11

Function = site of respiration and therefore ATP production.

Question 12

Describe the structure of centrioles.

Answer 12

Structure = hollow cylinders containing microtubules.

Question 13

Describe the function of centrioles.

Answer 13

Function = involved in cell division.

Question 14

Describe the structure of ribosomes.

Answer 14

Structure = composed of two subunits, maybe either be attached to rER or free in the cytoplasm, no surrounded by membrane.

Question 15

Describe the function of ribosomes.

Answer 15

Function = site of protein synthesis.

Question 16

Describe the function of lysosomes.

Answer 16

Function=break down any of the cell’s waste, destroy disease-causing organisms that enter the cell.

Question 17

Outline the role of the RER

Answer 17

Where proteins produced on the ribosomes of RER are folded and packaged into vesicles to be sent to Golgi apparatus.

Question 18

Outline the role of the Golgi apparatus with respect to proteins

Answer 18

Modified (e.g. adding of sugar chainn) and repackaged into secretory vesicles to be transported out of the cell by exocytosis.

Question 19

Describe the structure of the cell wall of a bacteria cell

Answer 19

Structure = forms a rigid outer covering over the cell, made of peptidoglycan.

Question 20

Describe the function of the cell wall.

Answer 20

Function = provides strength, support, protection against damage.

Question 21

Describe the structure of a plasmid.

Answer 21

Structure = circular molecules of DNA.

Question 22

Describe the function of a plasmid.

Answer 22

Function = DNA replication, transferring DNA between bacteria.

Question 23

Describe the structure of the flagellum.

Answer 23

Structure = a long, thin projection attached to the cell wall.

Question 24

Describe the function of the flagellum.

Answer 24

Function = movement; propels the cell forwards using a corkscrew motion.

Question 25

Describe the structure of the pili.

Answer 25

Structure = hair-like extensions on the surface of bacterial cells.

Question 26

Describe the function of the pili.

Answer 26

Function = help cells adhere to various surfaces, primarily each other, transfer of genetic material.

Question 27

Describe the structure of mesosomes.

Answer 27

Structure = infolds of the plasma membrane.

Question 28

Describe the function of mesosomes.

Answer 28

Function = site of respiration/unknown.

Question 29

How does DNA in prokaryotes differ to eukaryotes?

Answer 29

Circular not linear, not membrane bound in a nucleus, forms plasmids

Question 30

Explain the role of mitosis.

Answer 30

Produces genetically identical daughter cells. Useful for growth, repair, and (in prokaryotic cells) asexual reproduction.

Question 31

Outline interphase

Answer 31

Cell carries out normal functions but also prepares to divide by replicating DNA, cell components and making relevant proteins

Question 32

What happens in gap phase 1

Answer 32

Cell grows and new organelles and proteins are made

Question 33

What happens in the synthesis fase

Answer 33

Cell replicates its DNA ready for mitosis

Question 34

What happens in gap phase 2

Answer 34

Proteins needed for cell division are made

Question 35

Why are there checkpoints throughout the cycle

Answer 35

To ensure each stage is correctly carried out in order to avoid uncotrolled cell division leading to tumours

Question 36

Order the divino stages of mitosis

Answer 36

prophase, metaphase, anaphase, telophase

Question 37

Outline what happens in prophase

Answer 37

Chromosomes condense, centrioles move to opposite ends of the cells, the spindle forms and the nuclear envelope breaks down

Question 38

Outline what happens in metaphase

Answer 38

The chromosomes (now each with two chromatids) line up on the spindle equator

Question 39

Outline what happens in anaphase

Answer 39

The chromatids are pulled to opposite ends of the cell along the spindle fibres- centromere first

Question 40

Outline what happens in telophase

Answer 40

The chromatids decondense to form chromosomes, the nuclear envelope forms around each new nuclei and the cytoplasm divides (cytokinesis)