Cell Structure

Question 1

What is the structure of the nuclear envelope?

Answer 1

The nuclear envelope is a double membrane that surrounds the nucleus. Its outer membrane is continuous with the rough endoplasmic reticulum and has ribosomes on its surface.

Question 2

What is the function of the nuclear envelope?

Answer 2

The nuclear envelope controls the movement of substances into and out of the nucleus.

Question 3

What is the function of nuclear pores?

Answer 3

Nuclear pores allow large molecules, like messenger RNA (mRNA), to pass out of the nucleus.

Question 4

What are two structural features of the nucleolus?

Answer 4

The nucleolus is a dense, spherical region within the nucleoplasm.

Its function is to produce ribosomal RNA (rRNA) and assemble ribosomes.

Question 5

How does the nucleus control cell activities?

Answer 5

The nucleus is a control center that produces mRNA and tRNA, which are used in protein synthesis.

Question 6

What are chromosomes made of?

Answer 6

Chromosomes are made of linear DNA bound to proteins.

Question 7

What are the three functions of the nucleus in a eukaryotic cell?

Answer 7

1.Nucleus control cell activities via a production of mRNA and tRNA. 2.It stores genetic material in the form of DNA and chromosomes. 3. synthesises ribosomal RNA and assembles ribosomes.

Question 8

What is the role of the nucleoplasm in the nucleus?

Answer 8

The nucleoplasm is a jelly-like substance that supports the nuclear contents.

Question 9

What is the shape and size of a mitochondrion?

Answer 9

A mitochondrion has a rod-shaped structure with a double membrane.

Question 10

State the structure of the nucleus in a eukaryotic cell

Answer 10

Nucleus contains genetic information in the form of chromosomes. It contains a dense, spherical region nucleolus and is surrounded by a nuclear envelope containing pores.

Question 11

What is the role of cristae in mitochondria?

Answer 11

Cristae is the inner membrane folded to increase the surface area for exzymes involved in respiration

Question 12

What does the matrix of the mitochondria contain and why is it important?

Answer 12

The matrix in the mitochondria contains enzymes, Dna, and ribsosomes to make their own proteins

Question 13

What is the structure of mitochondria?

Answer 13

1.Mitochondria contains matrix rich in enzymes 2.mitochondria is surrounded by a double membrane and the inner membrane is folded to form a cristae. 3. mitochondria also contains their own DNA and ribosomes to synthesise their proteins

Question 14

What is the function of mitochondria?

Answer 14

Mitochondria function is to carry out aerobic respiration and produce ATP

Question 15

In which cells are mitochondria most abundant in and why?

Answer 15

Mitochondria is more abundant in metabolically active cells for contractions and active transport as the cells require a lot of ATP for their function

Question 16

Describe the structure of a chloroplast

Answer 16

Chloroplast are disc-shaped and have a double membrane

Question 17

What are grana and what are their function?

Answer 17

Grana are stacks of thylakoids containing chlorophyll for light absorption. Grana increase surface area.

Question 18

What is the role of stroma in chloroplast?

Answer 18

Stroma are fluid filled matrix containing enzymes for sugar synthesis

Question 19

State three adaptations of chloroplast for photosynthesis

Answer 19

1. Large surface area (grana), 2. Contain their own DNA and ribosomes for efficient photosynthesis.

Question 20

What is the structure and the main functions of rough endoplasmic reticulum RER?

Answer 20

Rough endoplasmic reticulum have ribosomes on its surface and is responsible to synthesis and transport proteins and glycoproteins throughout the cell.

Question 21

What are the characteristics and functions of smooth endoplasmic reticulum SER?

Answer 21

Smooth endoplasmic reticulum have no ribsomes on its surface and its function is to synthesis, store and transport lipds and carbohydrates. SER are abundant in liver and secretory cells.

Question 22

Describe the structure of Golgi apparatus

Answer 22

Gogi apparatus are a stack of flattened membranes (cristernae) with vesicles

Question 23

What are the five functions of Gogi apparatus?

Answer 23

1.Gogi apparatus modifies proteins by adding carbohydrates to glycoproteins. 2. Produces Secretory enzymes. 3. Secretes carbohydrates. 4. Forms lysosomes 5. Stores and modifies lipids.

Question 24

In which cell are Gogi apparatus most abundant in?

Answer 24

Secretory cells (which produces and transports proteins, enzymes, or mucus in intestines or pancreas)

Question 25

How do lysosomes form and what do they contain?

Answer 25

Lysosomes form from Golgi apparatus vesicles and contain digestive enzymes

Question 26

What are the four functions of lysosomes?

Answer 26

1. Digest pathogens, 2. Break down old organelles, 3. Carry out autolysis- self-destruction of cells, 4. Exocytosis- release enzymes outside of the cell

Question 27

In which type of cells are lysosmoes abundant in?

Answer 27

Abundant in phagocytes and secretory cell

Question 28

What are the two types of ribosomes and where are they found?

Answer 28

80s ribosomes are found in eukaryotes. 70s ribosomes are found in prokaryotes, mitochondria and chloroplasts

Question 29

What do ribosomes contain and what are their function?

Answer 29

Ribosomes are made up of proteins and ribosomal RNA rRNA, and its function is to synthesise proteins

Question 30

Where are ribosomes found in cells?

Answer 30

Ribosome are found in cytoplasm or attached to rough endoplasmic reticulum

Question 31

In which organisms are cell walls found in and what are they made of?

Answer 31

Cell walls are found in plants, algae and fungi. Cell walls are made up of cellulose microfibrils in plants and chitin in fungi

Question 32

State three functions of the cell wall

Answer 32

1. Cell wall prevents osmotic busting. 2. Provide mechanical strength. 3. Allows water transport between cells.

Question 33

What is the role of the middle lamella in cell walls?

Answer 33

Middle lamella in cell walls stick adjacent cells together

Question 34

Describe the structure and contents of a plant cell vacuole

Answer 34

A plant cell vacuole has a single membrane and contains a fluid with sugars, salts, amino acids, pigments

Question 35

State the 3 functions of the cell vacoule

Answer 35

1. Maintains turgidity, 2.stores nutrients and waste 3.contains pigments that attracts pollinators

Question 36

What do many mitochondria and dense cristae suggest about a cell’s function?

Answer 36

Many mitochondria in cell suggest the cell has high metabolic rate and dense cristae in mitochondria suggests greater production of ATP

Question 37

What does extensive roungh endoplasmic reticulum and Gogi apparatus indicate about a cell?

Answer 37

Extensive rough endoplasmic reticulum suggest high protein synthesis and abundant Gogi suggests high secretion