cells (con't)

Question 1

Process of protein synthesis and secretion

Answer 1

• Polypeptide chains are synthesized at the ribosomes and folded at the rough endoplasmic reticulum
• transport resides containing substances made by the endoplasmic reticulum pinched off from the ER
• these transport vesicles then fuse and then release their substances into the Golgi apparatus
• these substances are chemically modified and packaged inside the Golgi apparatus
• Secretary vesicles containing these modified substances are pinched off from the Golgi apparatus
• the secretary vesicles move towards and fuse with the cell membrane, releasing the substances outside the cell by exocytosis

Question 2

Process of formation of lysosomes

Answer 2

• Enzyme contents are synthesized on the RER and transported via transport vesicles to the Golgi apparatus for further processing
• A vesicle containing the processed enzymes buds off from the Golgi apparatus, forming a lysosome
• the enzymes have to be kept apart from the rest of the cell or else they would destroy the cell

Question 3

Similarities of animal and plant cells

Answer 3

Both cells contain cell membrane, mitochondria, nucleus and cytoplasm

Question 4

Differences of plant cell and animal cell (cell wall)

Answer 4

Plant cell: surrounded by the cell wall in addition to the cell membrane
Animal cell: cell wall is absent, only surrounded by the cell membrane

Question 5

Differences of plant cell and animal cell (chloroplasts)

Answer 5

Plant cell: chloroplasts are present in large number in photosynthetic cells
Animal cell: chloroplasts are absent

Question 6

Differences of plant cell and animal cell (centrioles)

Answer 6

Plant cell: centrioles are absent
Animal cell: centrioles are present

Question 7

Differences of plant cell and animal cell (vacuole)

Answer 7

Plant cell: present as a single, large and central vacuole
Animal cell: vacuoles are small and numerous

Question 8

Root hair cell

Answer 8

Adaptation: presence of long and narrow extension
Function: absorption of water and mineral salts, the surface area to volume ratio is increased due to the presence of long narrow extension, which increases the rate of diffusion of mineral salts and osmosis

Question 9

Red blood cell

Answer 9

Adaptation: presence of haemoglobin in the cytoplasm, absence of nucleus, biconcave shape
Functions: transport oxygen to other body cells.
Haemoglobin combines with oxygen. absence of nucleus will allow more haemoglobin to be packed in the cell, to bind to more oxygen. Biconcave shape increases SA: V to increase rate of diffusion of oxygen and carbon dioxide

Question 10

Muscle cell

Answer 10

Adaptation: elongated and cylindrical in shape, contains many nuclei and mitochondria
Function: has numerous mitochondria to provide energy for the contraction of the muscle cell

Question 11

Macromolecule

Answer 11

1st in increasing order of complexity
Definition: A large complex molecule, such as nuclei acids, proteins, carbohydrates, and lipids, with relatively large molecular weight which are made up of small monomers linked together

Question 12

Organelle

Answer 12

2nd in increasing order of complexity
Definition: a differentiated structure within a cell which performs a specific function

Question 13

Cell

Answer 13

3rd in increasing order of complexity
Definition: the building blocks of life, simplest units that have all the characteristics of life

Question 14

Tissue

Answer 14

4th in increasing order of complexity
Definition: a group of similar cells which work together to perform a specific function

Question 15

Organ

Answer 15

5th in increasing order of complexity
Definition: a structure made up of different tissues working together to perform a specific function

Question 16

Organ system

Answer 16

6th in increasing order of complexity
Definition: several organs working together for a common purpose make up an organ system