General Biology 1: Active Transport

Questions and Answers

What is the primary function of the sodium-potassium pump?

To transport sodium ions out of the cell and potassium ions into the cell (correct)

To move ions with their concentration gradient

To transport sodium ions into the cell

To facilitate passive transport of molecules

What source of energy does the sodium-potassium pump utilize?

Energy from light photons

Energy from glucose metabolism

Energy from passive diffusion

Energy from ATP hydrolysis (correct)

Which process involves the release of large molecules from a cell into the extracellular space?

Exocytosis (correct)

Endocytosis

Facilitated diffusion

Passive transport

How does exocytosis primarily accomplish the release of substances?

By merging secretory vesicles with the cell membrane Signup and view all the answers

What role does primary active transport play with respect to ion balance in cells?

It maintains the proper ion balance and electrical potential Signup and view all the answers

What is the chromosome number in cells produced by meiotic division?

Reduced by half Signup and view all the answers

Which of the following best describes the process of mitosis?

Produces genetically identical cells Signup and view all the answers

Which process allows for genetic diversity in offspring?

Meiosis Signup and view all the answers

What is the main application of mitosis in organisms?

Cellular reproduction and repair Signup and view all the answers

What happens during the crossing over process in meiosis?

Homologous chromosomes exchange genetic material Signup and view all the answers

Who discovered the process of meiosis?

Oscar Hertwig Signup and view all the answers

Which phase occurs during both mitosis and meiosis?

Metaphase Signup and view all the answers

What type of reproduction is exemplified by the budding process in organisms like hydra?

Asexual reproduction Signup and view all the answers

What is the primary function of peroxisomes?

Oxidize and break down fatty acids Signup and view all the answers

How do peroxisomes compare in size to centrosomes?

Usually smaller than centrosomes Signup and view all the answers

What shape do peroxisomes typically have?

Round Signup and view all the answers

What distinguishes eukaryotic cells from prokaryotic cells?

Eukaryotic cells have a defined nucleus Signup and view all the answers

What is a notable feature of the cell wall in eukaryotic cells?

It is enclosed by a membrane Signup and view all the answers

What is diffusion?

The random movement of particles from high to low concentration Signup and view all the answers

Which type of protein allows for the selective passage of ions and small polar molecules?

Channel proteins Signup and view all the answers

How do carrier proteins function in passive transport?

They bind to specific molecules and change shape to transport them. Signup and view all the answers

What is the role of transport proteins in passive transport?

To facilitate movement of substances that cannot easily pass through the lipid bilayer Signup and view all the answers

What is an example of a channel protein?

Aquaporin Signup and view all the answers

Which statement about diffusion is correct?

Diffusion always leads to equilibrium. Signup and view all the answers

What distinguishes carrier proteins from channel proteins?

Carrier proteins selectively bind and change shape. Signup and view all the answers

What is meant by the term 'concentration gradient'?

A difference in the concentration of a substance across a distance Signup and view all the answers

What material predominantly makes up chromatin?

DNA bound to protein Signup and view all the answers

Which characteristic is true for prokaryotic cells?

They are typically very small with a simple structure Signup and view all the answers

What function does the cytoskeleton serve in a cell?

Help maintain the cell’s shape and aid in movement Signup and view all the answers

Which of the following classifications includes prokaryotic organisms?

Eubacteria Signup and view all the answers

Which component is NOT typically found in prokaryotic cells?

Nucleus Signup and view all the answers

What additional layer may some prokaryotes possess?

Capsule Signup and view all the answers

Which statement best describes ribosomes in prokaryotic cells?

They serve as the site of protein synthesis Signup and view all the answers

How does the DNA in prokaryotic cells differ compared to eukaryotic cells?

It is circular and not enclosed in a membrane Signup and view all the answers

What role do flagella serve in some prokaryotic cells?

They assist in cellular movement Signup and view all the answers

What is a significant difference between prokaryotic and eukaryotic cells?

Prokaryotic cells have no membrane-bound organelles Signup and view all the answers

Study Notes

Primary Active Transport

Direct energy usage to transport molecules or ions against their concentration gradient.
Transmembrane proteins, known as pumps, facilitate this process.
Key example: Sodium-potassium pump (Na+/K+ pump) transports sodium (Na+) out and potassium (K+) into cells.
The pump relies on ATP hydrolysis to function, essential for maintaining ion balance and electrical potential across membranes.

Exocytosis

Opposite of endocytosis, allowing large molecules to exit the cell.
Merges secretory vesicles containing materials with the cell membrane, releasing contents into extracellular space.
Vital for secreting hormones, neurotransmitters, digestive enzymes, and incorporating new membrane components.

Mitosis

Produces identical cells for growth, repair, and reproduction.
Results in no pairing of homologous chromosomes, no crossing over.
Stages: Prophase, Metaphase, Anaphase, Telophase.
Applications include:
- Development and growth from a single cell.
- Constant replacement of cells (e.g., red blood cells have a lifespan of about four months).
- Repair of damaged tissues (e.g., starfish regenerating lost arms).
- Asexual reproduction in organisms like hydra, which reproduce by budding.

Meiosis

Involves disjunction, reducing chromosome number by half.
Promotes genetic diversity through sexual reproduction.
Stages: Prophase I & II, Metaphase I & II, Anaphase I & II, Telophase I & II.

Types of Passive Transport

Facilitates movement of substances across membranes without energy use.
Includes diffusion, where solutes move from high to low concentration down their gradient.

Types of Transport Proteins

Channel Proteins:
- Form pores to allow specific ions or polar molecules to pass through.
- Highly selective; example: aquaporin facilitates water movement.
Carrier Proteins:
- Bind to specific molecules, undergo conformational changes to transport them across the membrane.

Prokaryotic Cells

Simple cellular structure, typically very small.
DNA is not enclosed in a membrane.
Common features: Ribosomes, cytoplasm, some may have a protective capsule, and flagella for movement.

Differences Between Animal Cells and Plant Cells

Size: Animal cells generally smaller; plant cells larger.
Shape: Animal cells are round; plant cells are rectangular (fixed).
Cell Wall: Animal cells lack a cell wall; plant cells are enclosed by one.

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Description

This quiz covers the concepts of primary active transport, including hypertonic, hypotonic, and isotonic solutions. You'll learn about how energy is utilized to transport molecules against their concentration gradient through transmembrane proteins known as pumps.