Cell Structure

Question 1

Describe the structure of the nucleus

Answer 1

Surrounded by the nuclear envelope

Nuclear pores allow substances to enter/exit

Dense nucleolus made of RNA and proteins

Question 2

Describe the function of the nucleus

Answer 2

Contains DNA coiled around chromatin

Controls cellular processes

Question 3

Describe the structure and function of the endoplasmic reticulum

Answer 3

Rough ER: Ribosomes attached for protein synthesis.

Smooth ER: Lipid synthesis

Question 4

Describe the structure and function of the golgi apparatus

Answer 4

Stack of membrane bound, flattened sacs. Molecules are processed in cisternae.

Vesicles bud off via exocytosis

Function: Modifies and packages proteins

Question 5

Describe the structure and function of ribosomes

Answer 5

Formed of RNA and proteins

Have a large sub unit which joins amino acids and small sub unit with mRNA binding site

Question 6

Describe the structure of a mitochondrion

Answer 6

Surrounded by a double membrane

Folded inner membrane forms cristae

Fluid matrix

Question 7

Describe the structure of a chloroplast

Answer 7

Thylakoids: Flattened discs, stacked to form grana, contain photosystems with chlorophyll

Intergranal lamallae: Tubes attach thylakoids in adjacent grana

Stroma: Fluid filled matrix

Question 8

Describe the structure of a chloroplast

Answer 8

Thylakoids: Flattened discs, stacked to form grana, contain photosystems with chlorophyll

Intergranal lamallae: Tubes attach thylakoids in adjacent grana

Stroma: Fluid filled matrix

Question 9

Describe the function of mitochondria and chloroplasts

Answer 9

Mitochondria: Site of aerobic respiration to produce ATP.

Chloroplasts: Site of photosynthesis to convert solar energy to chemical energy

Question 10

Describe the structure and function of a lysosome

Answer 10

Sac surrounded by a single membrane. embedded H+ pump maintains acidic conditions. contains digestive hydrolase enzymes

Question 11

Describe the structure and function of centrioles

Answer 11

Spherical group of 9 microtubules arranged in triplets

Migrate to opposite poles of cell during prophase and spindle fibres form between them

Question 12

Describe the structure and function of flagella

Answer 12

Hollow helical tube made of flagellin

Rotates to propel organism

Question 13

Describe the structure and function of cilia

Answer 13

Hair like protrusions on eukaryotic cells

Move back and forth rhythmically to sweep foreign substances

Question 14

Why is the cytoskeleton important?

Answer 14

Provides mechanical strength

Aids transports within cells - such as RNA, vesicles along microtubules using ATP

Make up centrioles and spindle fibres

Enables cell movement

Question 15

What resolution can be achieved with a light microscope?

Answer 15

0.2 micrometres

Question 16

What part of the cell is responsible for the destruction of damaged organelles?

Answer 16

Lysosomes

Question 17

What part of the cell is concerned with the synthesis and transport of lipids and steroids in the cell?

Answer 17

Smooth ER

Question 18

Outline the interrelationship between the organelles involved in the production and secretion of proteins

Answer 18

1. gene containing the instructions for the production of the protein is copied to mRNA
2. mRNA leaves via nuclear pore
3. mRNA attaches to ribosome (sometimes on RER)
4. Ribosome reads instructions and begins making protein
5. molecules are pinched off in vesicles and go towards the golgi apparatus
6. Vesicles fuse with golgi apparatus
7. Golgi apparatus processes and packages molecules
8. molecules are pinched off in vesicles from the golgi apparatus and move towards the cell surface membrane
9. Vesicles fuse with cell surface membrane
10. exocytosis

Question 19

How do prokaryotic cells compare to eukaryotic cells?

Answer 19

no membrane bound organelles
smaller ribosomes
circular DNA
DNA not surrounded by a membrane
Some have flagella

Question 20

Plant v animal cells

Answer 20

Plant cells have a cell wall: strength
Plant cells have a vacuole: maintains stability by making the cell turgid as it increases the pressure inside the cell