BARB UGA BIO 1108 EXAM 1
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS – UPDATED
FOR 2026 SUCCESS
What is the general composition of a plant?
✔✔ Plants typically consist of 50–75% water, with the remaining portion
being dry biomass. This biomass is primarily made of cellulose and lignin,
containing approximately 50% carbon, 42% oxygen, and 7% hydrogen.
Which structural elements are essential for plant growth and where are they found?
✔✔ The core structural elements are carbon, hydrogen, and oxygen. Plants
pull carbon from the atmosphere, while hydrogen and oxygen are primarily
absorbed from the water in the soil.
Why is carbon considered the foundation of a plant's structure?
✔✔ Carbon is the central building block that forms the molecular backbone
for essential plant compounds, such as proteins and starches.
How do nitrogen and phosphorus function as primary nutrients?
✔✔ Nitrogen and phosphorus are critical for the formation of DNA, RNA,
and ATP. Phosphorus is also a key component of the phospholipids that build
and maintain cell membrane integrity.
What role does potassium play in the physical structure of a plant?
✔✔ Potassium is vital for regulating turgor pressure within cells, which
provides the internal force needed for plants to maintain their upright shape
, Why do plants need nitrogen? -ANSWER✔✔DNA- nitrogenous bases: adenine,
guanine, cytosine, thymine
ATP
Chlorophyll (captures light energy in photosynthesis)
Amino acids (AA)/proteins
How do most plants obtain nitrogen? (with the assistance of free-living bacteria in
the soil) -ANSWER✔✔nitrogen fixation, nitrification, assimilation
nitrogen fixation -ANSWER✔✔the process by which atmospheric nitrogen gas is
converted to ammonia by free-living N-fixing bacteria in the soil. This ammonia
(NH3) mixes with water in the soil and becomes ammonium (NH4+).
Nitrification -ANSWER✔✔the process by which free-living nitrifying bacteria
living in the soil convert ammonium (NH4+) to nitrites (NO2-, 2 oxygens) which
are then converted by different free-living bacteria in the soil to nitrates (NO3-, 3
oxygens).
Assimilation -ANSWER✔✔the process by which plants take up nitrates (NO3-)
from the soil through their roots via nitrate transporters. Plants can also take up
ammonium (NH4+) through ammonium transporters
How do legumes obtain nitrogen? -ANSWER✔✔With the assistance of symbiotic
bacteria living in nodules in their roots
With the assistance of free-living bacteria in the soil
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS – UPDATED
FOR 2026 SUCCESS
What is the general composition of a plant?
✔✔ Plants typically consist of 50–75% water, with the remaining portion
being dry biomass. This biomass is primarily made of cellulose and lignin,
containing approximately 50% carbon, 42% oxygen, and 7% hydrogen.
Which structural elements are essential for plant growth and where are they found?
✔✔ The core structural elements are carbon, hydrogen, and oxygen. Plants
pull carbon from the atmosphere, while hydrogen and oxygen are primarily
absorbed from the water in the soil.
Why is carbon considered the foundation of a plant's structure?
✔✔ Carbon is the central building block that forms the molecular backbone
for essential plant compounds, such as proteins and starches.
How do nitrogen and phosphorus function as primary nutrients?
✔✔ Nitrogen and phosphorus are critical for the formation of DNA, RNA,
and ATP. Phosphorus is also a key component of the phospholipids that build
and maintain cell membrane integrity.
What role does potassium play in the physical structure of a plant?
✔✔ Potassium is vital for regulating turgor pressure within cells, which
provides the internal force needed for plants to maintain their upright shape
, Why do plants need nitrogen? -ANSWER✔✔DNA- nitrogenous bases: adenine,
guanine, cytosine, thymine
ATP
Chlorophyll (captures light energy in photosynthesis)
Amino acids (AA)/proteins
How do most plants obtain nitrogen? (with the assistance of free-living bacteria in
the soil) -ANSWER✔✔nitrogen fixation, nitrification, assimilation
nitrogen fixation -ANSWER✔✔the process by which atmospheric nitrogen gas is
converted to ammonia by free-living N-fixing bacteria in the soil. This ammonia
(NH3) mixes with water in the soil and becomes ammonium (NH4+).
Nitrification -ANSWER✔✔the process by which free-living nitrifying bacteria
living in the soil convert ammonium (NH4+) to nitrites (NO2-, 2 oxygens) which
are then converted by different free-living bacteria in the soil to nitrates (NO3-, 3
oxygens).
Assimilation -ANSWER✔✔the process by which plants take up nitrates (NO3-)
from the soil through their roots via nitrate transporters. Plants can also take up
ammonium (NH4+) through ammonium transporters
How do legumes obtain nitrogen? -ANSWER✔✔With the assistance of symbiotic
bacteria living in nodules in their roots
With the assistance of free-living bacteria in the soil
