ultrastructure of eukaryotes

Question 1

What are the organelles that are present in eukaryotic cells? (12)

Answer 1

Nucleus;
Endoplasmic reticulum (Both RER and ER);
Golgi apparatus;
Ribosomes;
Mitochondria;
Lysosomes;
Chloroplasts;
Plasma membrane;
Centrioles;
Cell wall;
Flagella;
Cilia

Question 2

What organelles are only present in plant cells? (3)

Answer 2

Cellulose cell wall;
Chloroplasts;
Vacuole

Question 3

Draw and label the structure of a nucleus (4)

Answer 3

Nucleolus;
Nuclear envelope;
Chromatin;
Nuclear pores

Question 4

What does the nucleus contain within its structure to accommodate for its function? (3)

Answer 4

Histones (protein);
Linear DNA;
One or more RNA nucleoli

Question 5

What is the function of the nucleus? (2)

Answer 5

Contains and produces genetic material (DNA and RNA);

Controls protein synthesis;

So controls the development and function of the cell

Question 6

What components make up the structure of ribosomes? (2)

Answer 6

Proteins;
Ribosomal RNA

Question 7

What is the function of the ribosomes? (2)

Answer 7

Site of translation in protein synthesis;

Translating mRNA sequence into a sequence of amino acids

Question 8

Draw the structure of the rough endoplasmic reticulum (1)

Answer 8

It looks a lot like a maze with ribosomes on its surface

Question 9

Describe the function of the rough endoplasmic reticulum (2)

Answer 9

Has ribosomes on its surface that produce secretory proteins (proteins that are released out of the cell);

These secretory proteins are sent to Golgi Apparatus for modification and packaging

Question 10

What is the difference in structure between the RER & SER? (1)

Answer 10

RER contains ribosomes on its surface, whereas, SER lacks ribosomes

Question 11

Draw the structure of Golgi apparatus (1)

Answer 11

It looks a lot like a wifi symbol

Question 12

Describe the several functions of the Golgi apparatus (3)

Answer 12

Adds carbohydrates to proteins received from the RER to form glycoproteins;

Packages proteins/glycoproteins into Golgi vesicles (sacks) for secretion;

Produces lysosomes - a type of Golgi vesicle that releases lysozymes (hydrolytic enzymes)

Question 13

What is the basic function of the plasma membrane? (1)

Answer 13

Controls the movement of substances into and out of the cell

Question 14

What are the roles of the organelles that are involved in the production, transport and release of proteins from eukaryotic cells? (5)

Answer 14

1. DNA in the nucleus codes for these proteins;
2. Ribosomes in the RER produce these proteins via protein synthesis;
3. Mitochondria produces the ATP that is required for protein synthesis;
4. Golgi apparatus packages and modifies these proteins into vesicles;
5. Vesicles fuse with the cell membrane and release proteins outside of cell by exocytosis

Question 15

Describe the functions of lysosomes (3)

Answer 15

Digests material that is taken in by phagocytosis;

Non-functioning organelles within the cell are engulfed and digested by lysosomes;

Releases enzymes outside of the cell

Question 16

Draw and label the structure of the mitochondria (8)

Answer 16

Matrix;
Enzymes;
Inner membrane;
Cristae;
(Circular) DNA;
Inter-membrane space; Ribosomes (70S);
Outer membrane

Question 17

What is the basic function of the mitochondria? (2)

Answer 17

Involved in aerobic respiration;

Which produces ATP

Question 18

Why may some cells have lots of mitochondria and could you give an example of a cell? (2)

Answer 18

To provide energy to cells that require a large amount of ATP;

E.g. muscle cells

Question 19

What is the basic function of the cell wall? (1)

Answer 19

Provides support, strength and shape to the cell

Question 20

What is the basic function of the chloroplasts? (2)

Answer 20

Contains chlorophyll;

Which absorbs light energy for photosynthesis (important for the light dependent stage of photosynthesis)

Question 21

Draw and label the structure of chloroplasts (8)

Answer 21

Lipid droplets;
Stroma;
Thylakoids;
Free ribosomes (70S);
Circular DNA;
Starch grains;
Membrane bound chromosomes;
Granum

Question 22

What is the granum that is found in chloroplasts? (1)

Answer 22

Stacked thylakoids

Question 23

How do granum join together to form grana (plural for granum)? (1)

Answer 23

Link together by thin pieces of membrane - lamellae

Question 24

What is the basic function of the large vacuole? (1)

Answer 24

Contains soluble sugars, salts and pigments

Question 25

What features of both chloroplasts and mitochondria demonstrate that they are formerly free-living bacteria that were absorbed into a larger cell? (2)

Answer 25

They both contain circular DNA; They both contain 70S ribosomes

Question 26

What are centrioles? (2)

Answer 26

Cylindrical structures found in animal cells; Component of cytoskeleton

Question 27

Draw the structure of centrioles (2)

Answer 27

Composed of microtubules; 9 microtubules organised into triplets

Question 28

What is the function of the centrioles? (2)

Answer 28

Two centrioles at right angles to each other form a centrosome; This organises the spindle fibers during cell division

Question 29

Draw the structure of cilia (2)

Answer 29

Hair-like projections; Made of microtubules

Question 30

What is the function of cilia? (2)

Answer 30

Allow the movement of substances over the cell surface

Question 31

Draw the structure of flagella (2)

Answer 31

Similar structure to cilia; Made of longer microtubules

Question 32

What is the cytoskeleton? (1)

Answer 32

Network of protein filaments and tubules in the cytoplasm of many living cells

Question 33

What is features form the importance of the cytoskeleton? (4)

Answer 33

Provides mechanical strength to cells; Aids in the movement of molecules within the cell; Maintains the shape of cells; Forms both cilia and flagella

Question 34

What structures of the cytoskeleton allow it to carry out its function? (1)

Answer 34

Microtubules