Basic components of living systems

Question 1

What is the purpose of the nucleus and how does it affect cell metabolism? (2)

Answer 1

• Contains genetic information in the form of DNA. (1)
• Directs the synthesis of proteins (vital for cell metabolism). (1)

Question 2

Fill in the blanks:

DNA associates with proteins called histones to form ___. This coils and condenses forming ___. (2)

Answer 2

• Chromatin (1)
• Chromosomes (1)

Question 3

The nucleolus is responsible for creating ribosomes. How does it do this? (2)

Answer 3

• The nucleolus contains RNA and proteins. (1)
• rRNA is formed and combined with the proteins to form ribosomes. (1)

Question 4

Fill in the blanks about mitochondria (3):

Mitochondria is the site of the final stages of c___ r___. This is done by the production of ___. The amount of mitochondria in a cell reflects the amount of ___ used by the cell.

Answer 4

• Cellular respiration (1)
• ATP (1)
• Energy (1)

Question 5

What are vesicles and lysosomes? (3)

Answer 5

• Vesicles are (membranous) sacs that transport materials in the cell. (1)
• Lysosomes are a type of vesicle containing hydrolytic enzymes. (1)
• Hydrolytic enzymes break down waste material in the cell/pathogens. (1)

Question 6

What are the three components of the cytoskeleton (smallest to largest)? (1)

Describe the main functions of each. (3)

Answer 6

• Microfilaments; cell movement. (1)
• Intermediate fibres; mechanical strength. (1)
• Microtubules; structural support (shape of cell)/tracks for the movement of organelles around the cell/forms spindle fibres in cell division. (1)

Question 7

What are centrioles and what is their main function? (1)

Two centrioles form a ___. (1)

Answer 7

Structures composed of microtubules (1) that helps organise/assemble spindle fibres during cell divsion. (1)

Centrosome. (1)

Question 8

What are flagella responsible for? (1)

Answer 8

Cell motility/detecting chemical changes (1)

Question 9

Explain the different functions of smooth and rough endoplasmic reticulum. (2)

Answer 9

• SER; lipid and carbohydrate synthesis and storage. (1)
• RER; ribosomes bound to surface that facilitate the synthesis of proteins and their transport. (1)

Question 10

What is the function of the golgi apparatus? (1)

Answer 10

Modifies and ‘packages’ proteins into vesicles (secretory vesicles or lysosomes). (1)

Question 11

Fill in the blanks about vacuoles (4):

Vacuoles are ___ lined sacs that contain cell ___. They are important in many plant cells in the maintenance of ___, maintaining the rigid structure of the cell. The membrane of the vacuole, the ___, is selectively permeable.

Answer 11

• Membrane (1)
• Sap (1)
• Turgor (1)
• Tonoplast (1)

Question 12

What is the fluid enclosed in chloroplasts called? (1)

What are grana? (1)

What is the purpose of grana? (1)

Answer 12

• Stroma (1)
• Stacked thykaloids that are connected by lamellae (internal network of membranes). (1)
• Membranes maximise surface area for enzymes, proteins and chlorophyll (which are needed in photosynthesis). (1)

Question 13

What are the differences between how DNA is present in prokaryotes and eukaryotes. (4)

Answer 13

• In prokaryotes; DNA is stored in the cytoplasm (1), coiled. (1) (Some DNA is stored as plasmids.)
• In eukaryotes; DNA is stored in the nucleolus (1) and is linear. (1)

Question 14

What is the difference between ribosomes in eukaryotes and prokaryotes. (1)

Answer 14

Eukaryotes have bigger ribosomes/eukaryotes have 80S ribosomes while prokaryotes have 70S ribosomes. (1)

Question 15

The cell walls of plant cells are made out of cellulose - what are the cell walls of prokaryotes made from? (1)

Answer 15

Peptidoglycan/murein (1)

Question 16

Prokaryotes lack mitochondria, but still use ATP - how? (1)

Answer 16

ATP is supplied by chemiosmosis. (1)