📄 9th Grade Biology: Cell Structure and Function Worksheet
📌 1. True / False
1. Plant cells have cell walls, but animal cells do not.
2. Mitochondria are responsible for photosynthesis.
3. Prokaryotic cells have a true nucleus.
4. The cell membrane is selectively permeable.
5. Ribosomes are involved in protein synthesis.
✏️ 2. Fill in the Blanks
1. The is often called the "powerhouse of the cell."
2. Genetic material in eukaryotic cells is stored in the .
3. Plant cells contain for photosynthesis.
4. The jelly-like substance filling the cell and surrounding organelles is the .
5. The is a rigid outer layer that provides support and protection to plant cells.
🔗 3. Matching
« Contains the cell's genetic material and controls cell activities.
« Site of cellular respiration and ATP production.
« Site of photosynthesis in plant cells.
« Regulates the passage of substances into and out of the cell.
« Stores water, nutrients, and waste products; very large in plant cells.
✍️ 4. Short Answer Questions
1. Briefly explain the main difference between prokaryotic and eukaryotic cells.
💡 Suggested Answer: Prokaryotic cells lack a true nucleus and membrane-bound organelles, while eukaryotic cells possess both.
2. Name two organelles found in plant cells but not in animal cells.
💡 Suggested Answer: Cell wall and chloroplasts.
🎯 5. Multiple Choice
1. Which organelle is responsible for packaging and modifying proteins for secretion?
2. What is the primary function of the cell membrane?
3. Which of the following is NOT found in a typical animal cell?
📝 6. Open-Ended Questions
1. Describe the structure and function of the endoplasmic reticulum (ER) in a eukaryotic cell.
💡 Solution Steps:
The endoplasmic reticulum (ER) is a network of membranes found throughout the cytoplasm of eukaryotic cells, continuous with the outer nuclear membrane. There are two main types:
1. <strong>Rough ER</strong>: Studded with ribosomes, it is primarily involved in the synthesis, folding, modification, and transport of proteins that are destined for secretion or insertion into membranes.
2. <strong>Smooth ER</strong>: Lacks ribosomes and is involved in lipid synthesis, detoxification of drugs and poisons, and storage of calcium ions.
2. Explain how the structure of the cell membrane contributes to its function of selective permeability.
💡 Solution Steps:
The cell membrane is a fluid mosaic model composed primarily of a phospholipid bilayer with embedded proteins.
* <strong>Phospholipid Bilayer</strong>: The hydrophobic tails of the phospholipids face inward, forming a barrier to water-soluble molecules, while the hydrophilic heads face outward towards the aqueous environments. This structure allows small, nonpolar molecules (like O\(_2\) and CO\(_2\)) to pass through directly.
* <strong>Embedded Proteins</strong>: Various proteins are embedded within or span the bilayer. These include channel proteins, carrier proteins, and pumps, which facilitate or actively transport specific ions and larger molecules (like glucose and amino acids) across the membrane.
Together, these components ensure that the membrane controls which substances enter and exit the cell, maintaining the cell's internal environment.
3. Compare and contrast the functions of mitochondria and chloroplasts.
💡 Solution Steps:
Both mitochondria and chloroplasts are organelles involved in energy transformation within eukaryotic cells, but they have distinct functions.
* <strong>Mitochondria</strong>: They are the "powerhouses" of the cell, responsible for cellular respiration. In this process, glucose and oxygen are converted into ATP (adenosine triphosphate), which is the main energy currency of the cell, along with carbon dioxide and water. This occurs in both plant and animal cells.
* <strong>Chloroplasts</strong>: Found only in plant cells and some protists, chloroplasts are the sites of photosynthesis. They capture light energy from the sun and convert it into chemical energy in the form of glucose, using carbon dioxide and water, while releasing oxygen as a byproduct.
<strong>Contrast</strong>: Mitochondria break down organic molecules to release energy (catabolism), while chloroplasts build organic molecules using light energy (anabolism). They represent opposite but complementary energy conversion processes in the ecosystem.
Name Surname: .................................. Date: .... / .... / 202...
Cell Structure and Function Worksheet
SCORE
A. True (T) / False (F)
( .... )
Plant cells have cell walls, but animal cells do not.
( .... )
Mitochondria are responsible for photosynthesis.
( .... )
Prokaryotic cells have a true nucleus.
( .... )
The cell membrane is selectively permeable.
( .... )
Ribosomes are involved in protein synthesis.
B. Fill in the Blanks
1)
The .................... is often called the "powerhouse of the cell."
2)
Genetic material in eukaryotic cells is stored in the .....................
3)
Plant cells contain .................... for photosynthesis.
4)
The jelly-like substance filling the cell and surrounding organelles is the .....................
5)
The .................... is a rigid outer layer that provides support and protection to plant cells.
C. Matching Concepts
( .... )
Contains the cell's genetic material and controls cell activities.
- Cell Membrane
( .... )
Site of cellular respiration and ATP production.
- Chloroplast
( .... )
Site of photosynthesis in plant cells.
- Mitochondrion
( .... )
Regulates the passage of substances into and out of the cell.
- Nucleus
( .... )
Stores water, nutrients, and waste products; very large in plant cells.
- Vacuole
D. Short Answer Questions
1)
Briefly explain the main difference between prokaryotic and eukaryotic cells.
2)
Name two organelles found in plant cells but not in animal cells.
E. Multiple Choice Questions
1)
Which organelle is responsible for packaging and modifying proteins for secretion?
A) MitochondrionB) RibosomeC) Golgi apparatusD) Endoplasmic Reticulum (Rough)
2)
What is the primary function of the cell membrane?
A) To produce energy for the cell.B) To store genetic information.C) To control what enters and leaves the cell.D) To carry out photosynthesis.
3)
Which of the following is NOT found in a typical animal cell?
A) NucleusB) Cell wallC) CytoplasmD) Mitochondrion
F. Open-Ended Questions
1)
Describe the structure and function of the endoplasmic reticulum (ER) in a eukaryotic cell.
2)
Explain how the structure of the cell membrane contributes to its function of selective permeability.
3)
Compare and contrast the functions of mitochondria and chloroplasts.