Biology - Topic 1 Cell Structure and Transport Flashcards
Describe the basic unit of life.
The cell.
Define the two main types of cells.
Prokaryotic and Eukaryotic.
How does a prokaryotic cell differ from a eukaryotic cell?
A prokaryotic cell lacks a nucleus, while a eukaryotic cell has a nucleus.
Explain the role of the cell membrane.
It controls what enters and leaves the cell.
What is the primary function of the nucleus in a cell?
It contains DNA and controls the cell’s activities.
Identify where respiration occurs in a cell.
In the mitochondria.
What is the purpose of ribosomes in a cell?
To make proteins.
Describe the cytoplasm.
A jelly-like substance where most chemical reactions occur.
What structure provides support to plant cells?
The cell wall.
What is the composition of the cell wall in plant cells?
Cellulose.
Identify the organelle responsible for photosynthesis.
The chloroplast.
What pigment is found in chloroplasts and what is its function?
Chlorophyll; it absorbs light for photosynthesis.
Explain the function of the large central vacuole in plant cells.
It stores cell sap and helps maintain cell structure.
Describe the function of lysosomes.
They break down waste materials and cellular debris.
Explain the role of the Golgi apparatus in a cell.
To modify, sort, and package proteins for secretion.
How does the endoplasmic reticulum (ER) function in a cell?
It transports substances within the cell; rough ER has ribosomes, smooth ER does not.
Identify the part of the cell responsible for lipid production.
The smooth endoplasmic reticulum.
What is the primary function of the nucleolus?
It produces ribosomes.
Define passive transport in cellular processes.
The movement of substances across the cell membrane without energy input.
How does active transport differ from passive transport?
Active transport moves substances against a concentration gradient, requiring energy.
Define diffusion in the context of cellular movement.
The movement of particles from an area of high concentration to low concentration.
What factors influence the rate of diffusion?
Temperature, concentration gradient, and surface area.
Explain the process of osmosis.
The diffusion of water across a semi-permeable membrane from low to high solute concentration.
What characterizes a semi-permeable membrane?
A membrane that only allows certain substances to pass through.
Define a hypertonic solution in relation to cells.
A solution with a higher solute concentration than the cell, causing water to leave the cell.
Describe what happens to a cell in a hypotonic solution.
Water enters the cell, causing it to swell.
Define an isotonic solution.
A solution where the solute concentration is equal inside and outside the cell.
Explain the role of carrier proteins in active transport.
They help transport molecules across the cell membrane using energy.
How does facilitated diffusion occur?
The movement of molecules across the cell membrane through protein channels.
Why is ATP necessary for active transport?
Because it moves substances against their concentration gradient.
Describe the process of endocytosis.
The process of taking substances into the cell by engulfing them in a vesicle.
Define phagocytosis.
A type of endocytosis where the cell engulfs large particles or cells.
What occurs during exocytosis?
The process of releasing substances from the cell by vesicles fusing with the cell membrane.
Explain pinocytosis.
A type of endocytosis where the cell ingests liquids.
What is the function of protein channels in a cell membrane?
They allow specific molecules to pass through the cell membrane.
How do cells maintain homeostasis?
By regulating the movement of substances in and out of the cell.
Describe the sodium-potassium pump.
A type of active transport that moves sodium out of the cell and potassium into the cell.
Define selectively permeable.
It allows some substances to pass through while blocking others.
Describe the process by which plants absorb water.
Osmosis.
Identify the type of cells that have a flagellum.
Some prokaryotic cells and certain eukaryotic cells like sperm.
Explain why cells are small in size.
To maintain a large surface area-to-volume ratio for efficient transport.
What happens during plasmolysis?
The shrinking of a plant cell membrane away from the cell wall in a hypertonic solution.
How do amoebas move and obtain food?
By extending pseudopodia, which also helps them engulf food.
Define cytolysis.
The bursting of an animal cell in a hypotonic solution due to excess water intake.
What is a plasmid?
A small DNA molecule found in bacteria, separate from chromosomal DNA.
Explain the significance of root hair cells having a large surface area.
To increase the absorption of water and nutrients.
What is turgor pressure?
The pressure of the cell contents against the cell wall in plant cells.
Describe the process that occurs in the mitochondria that releases energy.
Cellular respiration.
How does osmosis relate to plant water absorption?
It is the process by which plants absorb water.
Identify the role of pseudopodia in amoebas.
They help in movement and engulfing food.
