Biology — Semester A Practice

Question 1 of 10

TEKS 1A-3F Easy Word Diagram

Which graph correctly shows exponential growth?

A Neither

B Both

C B

D A

Explanation

📌 Exponential growth = J-shaped curve (slow start, rapid increase)
Linear growth = straight line (constant rate)
Graph A shows exponential growth.

Question 2 of 10

TEKS 7A-7F Easy Word

Which scientist is credited with the theory of natural selection?

A James Watson

B Louis Pasteur

C Gregor Mendel

D Charles Darwin

Explanation

📌 Charles Darwin developed the theory of natural selection after studying finches in the Galápagos Islands.

Question 3 of 10

TEKS 4A-5D Medium Word Diagram

The diagram shows a cell in different solutions. In which solution will the cell shrink?

A C (Hypertonic)

B B (Isotonic)

C A (Hypotonic)

D All solutions cause shrinking

Explanation

📌 Hypertonic = more solute outside the cell
Water flows OUT of the cell by osmosis → cell shrinks (crenation)
Hypotonic → cell swells. Isotonic → no change.

Question 4 of 10

TEKS 1A-3F Easy Word

In a controlled experiment, what is the independent variable?

A The variable that is deliberately changed

B The variable that stays constant

C The control group

D The variable that is measured

Explanation

📌 The independent variable is what the scientist deliberately changes/manipulates.
The dependent variable is what is measured as a result.

Question 5 of 10

TEKS 1A-3F Easy Word

Which of the following is the BEST example of a hypothesis?

A Plants need water

B Photosynthesis is important

C If plants receive more sunlight, then they will grow taller

D All plants are green

Explanation

📌 A hypothesis is a testable, specific prediction.
'If plants receive more sunlight, then they will grow taller' is testable and specific.

Question 6 of 10

TEKS 1A-3F Medium Word Diagram

A student designed an experiment to test how light affects plant growth. Identify the components of this experiment.

A Independent: light; Dependent: plant height

B Independent: plant height; Dependent: light

C Independent: temperature; Dependent: light

D Independent: water; Dependent: soil

Explanation

📌 Independent variable = what you change (light)
Dependent variable = what you measure (plant height)
Control group = no light (to compare against)
Constants = same soil, water, temperature, pot size

Question 7 of 10

TEKS 4A-5D Easy Word

What is the function of the cell membrane?

A Makes proteins

B Produces energy

C Stores genetic information

D Controls what enters and exits the cell

Explanation

📌 The cell membrane is selectively permeable — it controls what enters and exits the cell.
It is made of a phospholipid bilayer.

Question 8 of 10

TEKS 4A-5D Easy Word Diagram

Which organelle is labeled X in the cell diagram below?

A Mitochondria

B Golgi apparatus

C Endoplasmic reticulum

D Nucleus

Explanation

📌 Organelle X has the bean-shaped structure with inner folds (cristae) → Mitochondria
Mitochondria = powerhouse of the cell = produces ATP through cellular respiration
C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Question 9 of 10

TEKS 8A-8C Easy Word

The scientific name for humans is Homo sapiens. 'Homo' represents the:

A family

B kingdom

C species

D genus

Explanation

📌 In binomial nomenclature: first word = Genus (capitalized), second = species (lowercase). Both italicized.

Question 10 of 10

TEKS 4A-5D Easy Word

Which organelle is responsible for producing energy (ATP) in the cell?

A Golgi apparatus

B Nucleus

C Ribosome

D Mitochondria

Explanation

📌 Mitochondria = 'powerhouse of the cell'
They convert glucose + oxygen → ATP through cellular respiration.

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