Eukaryotic and Prokaryotic Cells
What defines a eukaryotic cell?
Eukaryotic cells are defined by the presence of a nucleus that houses their DNA. They also have membrane-bound organelles.
What are plant cells?
Plant cells are the basic structural and functional units of plants. They are eukaryotic cells characterized by a rigid cell wall, chloroplasts for photosynthesis, and a large central vacuole.
What are the main components of an animal cell?
An animal cell consists of various organelles, including:
Nucleus: Contains the cell's genetic material (DNA) and controls cellular activities.
Cytoplasm: A gel-like substance where organelles are suspended and various metabolic reactions occur.
Cell membrane: A semi-permeable barrier that controls the movement of substances in and out of the cell.
Mitochondria: Known as the powerhouse of the cell, they generate ATP through cellular respiration.
Ribosomes: Sites of protein synthesis.
Endoplasmic Reticulum (ER):
Rough ER: Studded with ribosomes and involved in protein synthesis and processing.
Smooth ER: Involved in lipid synthesis and detoxification.
Golgi apparatus: Modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles.
Lysosomes: Contain enzymes for digestion of waste materials and cellular debris.
This organelle is known as the powerhouse of the cell, generating ATP through cellular respiration.
Mitochondria
What is a unicellular organism?
A unicellular organism is a living entity that consists of a single cell. These organisms can perform all necessary functions of life within that one cell.
What are some characteristics of prokaryotic cells?
Prokaryotic cells are characterized by the absence of a nucleus and membrane-bound organelles. Their DNA is found in a region called the nucleoid, and they are generally smaller and simpler than eukaryotic cells.
What is the purpose of the central vacuole?
The central vacuole serves multiple functions, including storing water and nutrients, aiding in cell growth by maintaining turgor pressure (the pressure of the cell content against the cell wall), and storing waste products.
How do animal cells differ from plant cells?
Animal cells differ from plant cells in several key ways:
Cell Wall: Animal cells lack a rigid cell wall, while plant cells have a cellulose cell wall that provides structure.
Chloroplasts: Animal cells do not contain chloroplasts, which are responsible for photosynthesis in plant cells.
Vacuoles: Animal cells may have small vacuoles, whereas plant cells typically have a large central vacuole that stores water and maintains turgor pressure.
Shape: Animal cells generally have irregular shapes, while plant cells tend to have a more defined, rectangular shape due to the cell wall.
This organelle is responsible for photosynthesis, converting sunlight into chemical energy in plant cells.
Chloroplasts
How do unicellular organisms reproduce?
Unicellular organisms primarily reproduce asexually through processes such as binary fission, budding, or fragmentation. Some may also engage in sexual reproduction.
What is the size difference between prokaryotic and eukaryotic cells?
Prokaryotic cells typically range from 0.1 to 5.0 micrometers in diameter, while eukaryotic cells are usually larger, ranging from about 10 to 100 micrometers or more.
What is the function of the chloroplast in plant cells?
Chloroplasts are organelles that conduct photosynthesis, converting sunlight, carbon dioxide, and water into glucose (a sugar) and oxygen. This process provides energy for the plant and is essential for life on Earth.
How do animal cells reproduce?
Animal cells typically reproduce through a process called mitosis, where a single cell divides into two genetically identical daughter cells. This process involves several stages: prophase, metaphase, anaphase, and telophase, followed by cytokinesis, where the cytoplasm divides. In the case of gametes (sperm and egg cells), a process called meiosis occurs, producing cells with half the number of chromosomes.
Often referred to as the cell's "control center," this organelle contains the genetic material.
Nucleus
How do unicellular organisms obtain energy?
Unicellular organisms obtain energy mostly through photosynthesis.
How do prokaryotic cells reproduce?
Prokaryotic cells reproduce asexually primarily through a process called binary fission, where a single cell divides into two identical daughter cells.
What is the function of ribosomes in plant cells?
Ribosomes are the sites of protein synthesis in all cells, including plant cells. They translate messenger RNA (mRNA) into proteins, which are essential for various cellular functions.
What function do mitochondria serve in animal cells?
Mitochondria are known as the "powerhouses" of the cell because they produce adenosine triphosphate (ATP) through the process of cellular respiration. ATP serves as the primary energy currency of the cell, powering various cellular processes.
These organelles are involved in the synthesis of proteins and can be found free-floating or attached to the endoplasmic reticulum.
Ribosomes
What is the difference between prokaryotic and eukaryotic unicellular organisms?
Prokaryotic unicellular organisms, such as bacteria, lack a nucleus and membrane-bound organelles. Eukaryotic unicellular organisms, such as protozoa and some algae, have a defined nucleus and organelles.
How do eukaryotic cells reproduce?
Eukaryotic cells can reproduce both asexually (e.g., through mitosis) and sexually (e.g., through meiosis), allowing for genetic diversity in offspring.
How do plant cells reproduce?
Plant cells can reproduce through a process called mitosis, where a single cell divides to produce two identical daughter cells. In some cases, plants can also reproduce asexually through processes like budding or fragmentation.
What is the role of the cell membrane in animal cells?
The cell membrane (also called the plasma membrane) serves as a protective barrier that regulates the entry and exit of substances. It is selectively permeable, meaning it allows certain molecules to pass while restricting others. This regulation is essential for maintaining homeostasis within the cell.
This organelle contains digestive enzymes that break down waste materials and cellular debris.
Lysosomes
What environments do unicellular organisms thrive in?
Unicellular organisms can be found in a variety of environments, including soil, water, extreme environments (like hot springs or deep oceans), and even inside other organisms.