PBL 1: The Plant Cell

Question 1

Amyloplasts

Answer 1

Plastids that stores starch: considered to be leucoplasts

Question 2

Proplastids

Answer 2

Undifferentiated young plastids common in meristematic cells.

Question 3

Chloroplasts

Answer 3

Chlorophyll-rich plastids that carry out photosynthesis

Question 4

Chromoplasts

Answer 4

Plastids that contain red/yellow pigments. They are located in flowers and fruits.

Question 5

Leucoplasts

Answer 5

Colorless plastids that synthesize lipids and other materials.

Question 6

Specialized function of shoot/root tip cells

Answer 6

Cell division: produces new protoplasm

Question 7

Specialized function of epidermis cells

Answer 7

Water retention; cutin and wax barriers against fungi and insects

Question 8

Specialized function of epidermal gland cells

Answer 8

Cell protection: produces poisons that prevent animals from harming plants

Question 9

Specialized function of green leaf cells

Answer 9

Collects solar energy via photosynthesis

Question 10

Specialized function of root epidermal cells

Answer 10

Collects water and minerals

Question 11

Specialized function of vascular cells

Answer 11

Transports water and minerals

Question 12

Specialized function of fruit cells

Answer 12

Produces sugars, aromas and flavourful compounds that attract fruit eating/seed dispersing animals.

Question 13

Cell membrane

Answer 13

Found in all cells: separates the interior of the cell from the external environment. Consists of a semipermeable lipid bilayer.
They:
-regulate the passage of molecules in and out
-divides the cell into numerous compartments
-acts as surfaces that hold enzymes

Question 14

Function of cell wall

Answer 14

-Provides strength, cellular communication and protection from chemical, fungal and bacterial attack.

Question 15

Molecular components of cell wall

Answer 15

-Cellulose molecules crystallise into microfibrils
-Hemicellulose binds the microfibrils
-Pectin

Question 16

Structural components of cell wall

Answer 16

-Primary cell wall (thin, flexible)

-Secondary cell wall (strengthens the primary cell wall, provides rigidity, located between primary cell wall and plasma membrane).
ONLY OCCURS IN CERTAIN CELL TYPES, E.G. tracheids, vessel elements, sclerenchyma

-Lamella: connects adjacent cells, acts like a glue, made of pectin

-Primary pit field: clustered regions of plasmodesmata

Question 17

Plasmodesmata (association of cells)

Answer 17

Membrane channels for cellular communication, ER passes through the channel.

Function: cell signalling
-Symplastic: protoplasm of all cells of one plant connect, transport within the cells

-Apoplastic: Intercellular spaces between cells and cell wall, transport within the middle lamella is more quick and efficient

Question 18

Function of Vacuole

Answer 18

Cell growth, digestion, storage of metabolic waste and nutrients

Question 19

Components of Vacuole

Answer 19

-Tonoplast: vacuole membrane, selectively permeable
-Salt and Water
-Anthocyanins (water-soluble pigments)

Question 20

Function of Plastids

Answer 20

Conducts metabolic functions including:
-Synthesis of amino acids
-Storage
-Export of specialized lipids, molecules, carbohydrates+iron
-Forms colors

Question 21

Components of Plastids

Answer 21

-Outer+inner membrane
-Inner fluid called stroma, contains DNA and ribosomes

Question 22

Etioplast

Answer 22

Plastid in the stage before specialising:
-Light exposure: chloroplast+chromoplast
-No light exposure: unpigmented leucoplast

Question 23

Microbodies

Answer 23

Use and produce peroxide and contain the enzyme catalase:
-Peroxisome: peroxide used to detoxify ROS in photosynthesis
-Glyoxysome: conversion of fats to sugars

Question 24

Nucleus

Answer 24

Stores genetic information

Components: DNA, nuclear pores, nuclear envelope

Question 25

Ribosome

Answer 25

Protein synthesis

Components: rRNA and proteins, large and small subunit

Question 26

Mitochondria

Answer 26

ATP synthesis

Components: matrix, inner membrane foldings (cristae), mit. DNA, double membrane

Question 27

Microtubules

Answer 27

Cytoskeleton and motility

Components: Alpha-tubulin and beta-tubulin

Question 28

Microfilaments

Answer 28

Structure and movement of cell

Components: Actin (protein)