Chapter 7 Lipid Metabolism

Question 1

Key Functions of Lipids in Plants (4)

Answer 1

Energy storage
Membrane structure
Signaling molecules
Thermal Protection

Question 2

serve as a concentrated source of energy.

Answer 2

Lipids

Question 3

____, stored in seeds and
other tissues, provide energy during periods of growth and development.

Answer 3

Triacylglycerols (TAGs)

Question 4

__, ___, and ___are fundamental components of cellular membranes,
contributing to membrane integrity, fluidity, and functionality.

Answer 4

Phospholipids, glycolipids, and sterols

Question 5

__ and ___ help plants retain moisture and protect against environmental
stressors, such as extreme temperatures and pathogens.

Answer 5

Waxes and cuticular lipids

Question 6

Types of Lipids in Plants

Answer 6

Fatty acids
Triglycerides
Phospholipids
Glycolipids
Sterols

Question 7

___ are carboxylic acids with long hydrocarbon chains

Answer 7

Fatty acids

Question 8

___ have no double bonds between carbon atoms, making them solid at room temperature,

Answer 8

Saturated fatty acids

Question 9

______ contain one or more
double bonds, which introduces kinks in their structure and keeps them liquid at
room temperature.

Answer 9

unsaturated fatty acids

Question 10

are the primary form of stored energy in plants, predominantly
found in seeds and some fruits.

Answer 10

Triglycerides

Question 11

are composed of three fatty acids attached to
a glycerol molecule.

Answer 11

Triglycerides

Question 12

During ____, triglycerides are broken down into fatty
acids and glycerol, providing energy and carbon skeletons for the growing plant.

Answer 12

germination

Question 13

They serve not only as energy reserves but also as thermal insulators and
protective agents

Answer 13

Triglycerides

Question 14

They consist of
two fatty acid tails, a glycerol backbone, and a phosphate group.

Answer 14

Phospholipids

Question 15

The unique
structure of phospholipids,

Answer 15

with hydrophilic (water-attracting) heads and
hydrophobic (water-repelling) tails,

Question 16

___are lipids that contain carbohydrate moieties

Answer 16

Glycolipids

Question 17

These molecules are typically found in the outer layer of the plasma
membrane and contribute to cell-cell interactions, which are crucial for processes
like immune response and tissue development

Answer 17

Glycolipids

Question 18

are a subgroup of lipids characterized by a four-ring structure

Answer 18

Sterols

Question 19

most common sterols are

Answer 19

sitosterol and stigmasterol.

Question 20

These compounds help to
maintain membrane fluidity and integrity, particularly under varying temperature
conditions.

Answer 20

sterols

Question 21

can also play roles in plant growth and development by
influencing hormone pathways and cell signaling mechanisms

Answer 21

Sterols

Question 22

Lipid Metabolism Pathways

Answer 22

Lipogenesis
Lipolysis

Question 23

location of lipogenesis

Answer 23

plastids, particularly in chloroplasts, and within
the endoplasmic reticulum (ER) of cells.

Question 24

Key process of lipogenesis

Answer 24

Fatty acid synthesis
Triglyceride formation
Lipid modification

Question 25

Fatty Acid Synthesis: The process begins with ____, which is derived from carbohydrates or proteins.

Answer 25

acetyl-CoA

Question 26

Fatty Acid Synthesis: Acetyl-CoA is converted to ____ by the enzyme _____

Answer 26

malonyl-CoA; acetyl-CoA carboxylase.

Question 27

Fatty Acid Synthesis: Malonyl-CoA is then used in the _____ to elongate the fatty acid chain in a series of condensation, reduction, dehydration, and reduction steps, producing ____ (usually C16 and C18).

Answer 27

fatty acid synthase complex; long-chain fatty acids

Question 28

Triglyceride Formation: Once fatty acids are synthesized, they are linked to ____ through ____, forming triglycerides.

Answer 28

glycerol-3-phosphate; esterification;

Question 29

Triglyceride formation: Triglycerides are primarily stored in specialized organelles known as ___, with a significant concentration found in seeds, which rely on these reserves for energy during germination

Answer 29

oil bodies or lipid droplets

Question 30

Lipid Modifications: ○ The synthesized fatty acids can undergo various modifications, including ___ and ____

Answer 30

desaturation and elongation.

Question 31

Lipid modification results in the formation of different lipid classes such as _____(important for cell membranes) and ____ (which play roles in cell recognition and signaling).

Answer 31

phospholipids ; glycolipids

Question 32

location of lipolysis

Answer 32

mainly occurs in the peroxisomes and mitochondria

Question 33

key process of lipolysis

Answer 33

Triglyceride hydrolysis Beta-oxidation Glyoxylate cycle

Question 34

Triglyceride hydrolysis: The breakdown of stored triglycerides starts with their hydrolysis into ___ and___, facilitated by enzymes ___

Answer 34

free fatty acids and glycerol; lipase

Question 35

The released free fatty acids are transported into peroxisomes and mitochondria for a process called ____

Answer 35

beta-oxidation.

Question 36

During beta-oxidation, fatty acids are broken down into ___, along with the production of reducing equivalents such as____ and ____

Answer 36

acetyl-CoA units; NADH and FADH2.

Question 37

Inplant seedlings, the ___ is a unique metabolic pathway that enables the conversion of acetyl-CoA, produced during fatty acid oxidation, into carbohydrates.

Answer 37

glyoxylate cycle

Question 38

This conversion is vital for supporting growth and energy needs during early development stages when seedlings rely on stored lipids before they can photosynthesize effectively

Answer 38

glyoxylate cycle

Question 39

Factors controlling the Lipid Metabolism

Answer 39

Hormonal Control Nutritional Status Environmental Factors Microbial Interactions

Question 40

Plant Hormones=

Answer 40

Phytohormones

Question 41

examples of phytohormones

Answer 41

Auxins abscisic acid ethylene

Question 42

: Can influence lipid accumulation by modulating cell growth and division.

Answer 42

Auxins

Question 43

Often increases during stress, promoting lipid mobilization for energy.

Answer 43

Abscisic Acid (ABA):

Question 44

: Affects lipid breakdown during fruit ripening and senescence.

Answer 44

Ethylene

Question 45

Nutritional Status depends on

Answer 45

Carbon Availability Nutrient Levels

Question 46

Excess carbohydrates can lead to increased lipid storage through pathways like

Answer 46

de novo fatty acid synthesis.

Question 47

Essential nutrients, such as __ and ___, play crucial roles in lipid metabolism

Answer 47

nitrogen and phosphorus

Question 48

____ can impair lipid synthesis, while sufficient levels promote healthy growth and storage.

Answer 48

Nitrogen deficiency

Question 49

Environmental Factors

Answer 49

Light Temperature stress condiitons

Question 50

Temperature fluctuations can alter lipid composition, particularly the ___, impacting membrane fluidity and metabolic rates.

Answer 50

fatty acid profile

Question 51

Environmental stressors (e.g., drought, salinity) can trigger alterations in lipid metabolism, often leading to the accumulation of stress-related lipids like___ and ___

Answer 51

phospholipids and fatty acid derivatives

Question 52

can influence lipid metabolism in plants by enhancing nutrient availability and promoting beneficial interactions that can modify metabolic pathways

Answer 52

Soil microbiota

Question 53

fatty acids modification can be utilized in

Answer 53

waxes cutin and suberin sterols