EOC Review Category 4: Biological
Processes and Systems (Answered)
2025/2026.
A multicellular organism begins as a single cell called a
zygote
This single cell is formed from the union of an egg and a sperm cell during fertilization. The single cell
divides into two daughter cells through mitosis. These cells continue to divide forming a fluid filled
ball of cells called a
blastula
Cell differentiation begins when some cells start to form tissues by moving inward to form
the__________________. Cell differentiation continues to occur by the expression of different genes
within the cells themselves. The internal and external environment can affect how these genes are
expressed.
gastrula.
blood
Erythrocytes carry oxygen and carbon dioxide through the use of hemoglobin.
muscle
Can be involuntary or voluntary and drive all movement within the animal.
, epithelium
Covers external surfaces and internal cavities. Forms boundaries and protects the tissues below from
damage and microorganisms.
stem
Xylem moves water and minerals from the roots to the leaves. Phloem moves nutrients throughout
the plant.
root
Epidermal cells on hairs increase surface area to allow for more absorption of water and minerals.
leaf
Cells contain chloroplasts for photosynthesis. Guard cells control the size of the stoma for gas
exchange and transpiration (evaporation of water).
tissue
group of similar cells that perform a particular function
Processes and Systems (Answered)
2025/2026.
A multicellular organism begins as a single cell called a
zygote
This single cell is formed from the union of an egg and a sperm cell during fertilization. The single cell
divides into two daughter cells through mitosis. These cells continue to divide forming a fluid filled
ball of cells called a
blastula
Cell differentiation begins when some cells start to form tissues by moving inward to form
the__________________. Cell differentiation continues to occur by the expression of different genes
within the cells themselves. The internal and external environment can affect how these genes are
expressed.
gastrula.
blood
Erythrocytes carry oxygen and carbon dioxide through the use of hemoglobin.
muscle
Can be involuntary or voluntary and drive all movement within the animal.
, epithelium
Covers external surfaces and internal cavities. Forms boundaries and protects the tissues below from
damage and microorganisms.
stem
Xylem moves water and minerals from the roots to the leaves. Phloem moves nutrients throughout
the plant.
root
Epidermal cells on hairs increase surface area to allow for more absorption of water and minerals.
leaf
Cells contain chloroplasts for photosynthesis. Guard cells control the size of the stoma for gas
exchange and transpiration (evaporation of water).
tissue
group of similar cells that perform a particular function
