B2. Cells Flashcards
(20 cards)
What is the function of the nucleus in a cell?
Contains genetic material (DNA).
What is the function of the mitochondria in a cell?
Site of aerobic respiration and energy release.
What is the function of the cell membrane?
Controls the movement of substances in and out of the cell.
What structures do plant cells have that animal cells do not?
Cell wall: Provides support and structure; made of cellulose.
Chloroplasts: Contain chlorophyll and are the sites of photosynthesis.
Large central vacuole: Maintains turgor pressure and stores water, nutrients, and waste.
Why is the cell wall important in plant cells?
The cell wall provides structural support and protection, helps maintain cell shape, and prevents excessive water uptake (turgor pressure).
What is photosynthesis, and where does it occur in plant cells?
Photosynthesis is the process by which plants convert light energy, carbon dioxide, and water into glucose (food) and oxygen. It occurs in chloroplasts.
What is the function of the large central vacuole in plant cells?
The vacuole stores water, nutrients, and waste products. It also helps maintain turgor pressure, which keeps the cell rigid and supports plant structure.
What structures are found in both animal and plant cells?
Nucleus: Contains genetic material (DNA).
Cytoplasm: Site of metabolic reactions.
Cell membrane: Controls the movement of substances in and out of the cell.
Mitochondria: Site of aerobic respiration and energy release.
What is the function of chloroplasts?
Chloroplasts are the site of photosynthesis, where light energy is used to convert carbon dioxide and water into glucose (food) and oxygen. They contain chlorophyll, a green pigment that absorbs light.
What are the key features of bacterial cells?
Cell wall: Provides structure and protection (not made of cellulose like plant cells).
Plasma membrane: Regulates the entry and exit of substances.
Cytoplasm: Where metabolic reactions occur.
Ribosomes: For protein synthesis
Single circular DNA chromosome: Free in the cytoplasm, not enclosed in a nucleus.
Plasmids: Small, circular DNA molecules that carry additional genes (e.g., for antibiotic resistance).
How do bacterial cells reproduce?
Bacteria reproduce through binary fission, a form of asexual reproduction where the DNA is replicated, and the cell splits into two identical daughter cells.
What is the function of the plasmid in bacterial cells?
They often carry genes that can provide the bacteria with survival advantages, such as antibiotic resistance.
What are specialized cells, and why are they important?
Specialized cells have specific structures that enable them to perform particular functions more efficiently. These adaptations make them crucial for the functioning of multicellular organisms.
Describe the structure and function of red blood cells.
Structure: Red blood cells are biconcave in shape, which increases their surface area for gas exchange. They have no nucleus, allowing more space for hemoglobin (which binds oxygen).
Function: Their main function is to carry oxygen from the lungs to tissues and bring carbon dioxide back to the lungs for exhalation.
Describe the structure and function of xylem cells.
Structure: Xylem cells are hollow tubes made from dead cells.
Function: Xylem transports water and minerals from the roots to the rest of the plant.
Describe the structure and function of phloem cells.
Structure: Phloem cells are living cells that contain sieve plates and companion cells.
Function: Phloem transports sucrose and other nutrients from the leaves (where they are produced through photosynthesis) to the rest of the plant.
What are the levels of organization, starting from the simplest?
Cell: Basic unit of life (e.g., muscle cell, red blood cell).
Tissue: A group of similar cells working together to perform a function (e.g., muscle tissue).
Organ: A structure made of several types of tissues working together to perform a specific function (e.g., heart, lungs).
Organ system: A group of organs that work together to perform a broader function (e.g., circulatory system, digestive system).
Organism: An individual living being made up of many organ systems (e.g., human, plant).
What is the formula for total magnification?
total magnification = (eyepiece lens magnification) × (objective lens magnification)
What is the formula for magnification?
size of image/size of object
How many micrometers in a centimeter?
10,000
