Biology Chapter 1 Flashcards

Questions and Answers

Describe the cytosol.

Part of the cytoplasm not contained within intracellular membranes. Acts like a water-based gel due to crowding of molecules. Early steps in breakdown of nutrient molecules takes place here, and most proteins are made by ribosomes here.

Describe the cytoskeleton.

Responsible for directed cell movements. Consists of actin filaments, microtubules, and intermediate filaments. Role in cell division may be its most ancient function.

What is the evidence for the theory that eukaryotic cells originated as predators?

Such a way of life requires large size, flexible membrane, and cytoskeleton to help cell move and eat. Nuclear compartment keeps DNA segregated from this, allowing more complex control of how genetic info is read.

What makes E. coli a model organism?

Focused on by molecular biologists. It has helped us learn how cells replicate DNA and decode it to make proteins. It grows and reproduces rapidly in a simple nutrient broth. Signup and view all the answers

Describe Brewer's yeast (Saccharomyces cerevisiae) as a model organism.

Small, single-celled fungus that reproduces as quickly as a bacterium and carries out all basic tasks of a eukaryotic cell. Genetic and biochemical studies focus on many mechanisms, especially the cell-division cycle. Signup and view all the answers

What is the significance of Arabidopsis thaliana as a model organism?

It can be grown indoors and reproduces rapidly. Genes have counterparts in agricultural species, providing insights into development and physiology of crop plants. Signup and view all the answers

Why is Drosophila melanogaster important in genetics?

Foundational in classical genetics. Recent studies focus on how genetic instructions direct the development of a zygote into an adult multicellular organism organized in a precise manner. Signup and view all the answers

What is Caenorhabditis elegans used for in research?

A valuable model for many development processes that occur in humans. Studies have led to a detailed molecular understanding of apoptosis. Signup and view all the answers

What are the advantages of using zebrafish as a model organism?

It is transparent for the first two weeks of life, allowing observation of how cells behave during development. Signup and view all the answers

Why are mice used as model organisms in research?

They are used to study mammalian genetics, development, immunology, and cell biology, with almost every human gene having a counterpart in mice. Signup and view all the answers

What is the significance of studying human cell cultures?

Many human cell types will survive, proliferate, and express specialized properties in a culture dish, allowing for various studies. Signup and view all the answers

The difference between transmission electron micrograph and scanning electron micrograph is that transmission produces a _ image while scanning produces a _ image.

2D, 3D Signup and view all the answers

Where does transcription and translation occur in a eukaryotic cell?

Transcription occurs in the nucleus, translation occurs in the cytoplasm. Signup and view all the answers

What is the central dogma?

DNA -> RNA -> Protein Signup and view all the answers

Genetic changes followed by selection are best described as the fundamentals of what process?

Evolution Signup and view all the answers

Which of the following is not a difference between liver cells and kidney cells in the same animal?

The different cells have different DNA. Signup and view all the answers

Which structure could not be seen using an electron microscope?

Electron Signup and view all the answers

What is a drawback to using light microscopy?

It cannot be used to view structures smaller than a bacterium. Signup and view all the answers

Which is the smallest object that can be seen using an electron microscope?

Individual molecule Signup and view all the answers

An individual ribosome can be seen with a fluorescence microscope.

True Signup and view all the answers

What do eukaryotic cells have that prokaryotes lack?

A nucleus and membrane-bound organelles Signup and view all the answers

At a molecular level, the members of the two domains of prokaryotes—the archaea and bacteria—differ as much from each other as either does from the eukaryotes.

True Signup and view all the answers

Like the differentiated cells in an individual plant or animal, all bacteria have the same DNA.

False Signup and view all the answers

One thing all cells have in common is an ability to colonize any environment on Earth.

False Signup and view all the answers

What organisms commonly colonize extreme environments?

Archaea Signup and view all the answers

Which organelle's ancestor was likely engulfed by primitive eukaryotes?

Mitochondrion Signup and view all the answers

What is the name of the process by which eukaryotic cells engulf material captured from an external medium?

Endocytosis Signup and view all the answers

Which of the following is a stack of flattened membrane-enclosed sacs?

Golgi apparatus Signup and view all the answers

Which cellular component separates the DNA of eukaryotic cells from the cytoplasm?

Nuclear membrane Signup and view all the answers

What is the model organism for the cell cycle?

The brewer's yeast, Saccharomyces cerevisiae. Signup and view all the answers

Which of the following is a model plant used by scientists?

Arabidopsis thaliana Signup and view all the answers

Explain how life is an autocatalytic process.

DNA and RNA provide the sequence info to produce proteins that catalyze the synthesis of DNA and RNA. Signup and view all the answers

What is the cell theory?

All living cells are formed by the growth and division of existing cells. Signup and view all the answers

What is the highest resolution of light microscopes?

0.2 um Signup and view all the answers

What are the simplest cells?

Bacteria Signup and view all the answers

What are the shapes of prokaryotes?

Spherical, rodlike, or corkscrew-shaped (spiral) Signup and view all the answers

Describe the membranes surrounding prokaryotes.

Most prokaryotes have a cell wall which surrounds the plasma membrane. Signup and view all the answers

Why can populations of prokaryotic cells quickly evolve?

Their large numbers, rapid proliferation, and ability to exchange bits of genetic material. Signup and view all the answers

Describe the nucleus.

It is surrounded by two concentric membranes that form the nuclear envelope and contains DNA. Signup and view all the answers

Describe mitochondria.

Mitochondria are enclosed in two membranes with the inner membrane folded for energy production. Signup and view all the answers

Describe chloroplasts.

Chloroplasts are found in plants and algae, involved in photosynthesis, and contain chlorophyll. Signup and view all the answers

Describe the endoplasmic reticulum (ER).

An irregular maze of interconnected spaces enclosed by a membrane for making cell components. Signup and view all the answers

Describe the Golgi apparatus.

Stacks of flattened membranes that modify and package molecules made in the ER. Signup and view all the answers

Describe lysosomes.

Lysosomes are where intracellular digestion occurs, recycling nutrients within the cell. Signup and view all the answers

Describe peroxisomes.

Small, membrane-enclosed vesicles for reactions using hydrogen peroxide to inactivate toxic molecules. Signup and view all the answers

How is the continual exchange of materials between the ER, Golgi apparatus, lysosomes, plasma membrane, and outside of cell mediated?

Transport vesicles pinch off from one organelle and fuse with another. Signup and view all the answers

Study Notes

Cell Function and Structure

Transcription occurs in the nucleus, while translation happens in the cytoplasm.
The central dogma of molecular biology is expressed as DNA -> RNA -> Protein.
Liver and kidney cells have the same DNA but express different genes and proteins, leading to distinct roles in the body.
Prokaryotic cells can evolve rapidly due to large populations and genetic material exchange.

Microscope Usage

Electron microscopes visualize structures as small as individual molecules by using electron beams.
Fluorescence microscopes can observe ribosomes due to advanced illumination techniques, achieving resolutions around 20 nm.
A significant limitation of light microscopy is its inability to resolve structures smaller than 0.5 µm.

Prokaryotic vs Eukaryotic Cells

Eukaryotic cells possess a nucleus and membrane-bound organelles, unlike prokaryotes.
All cells share key features, such as nucleic acids and ribosomes.
Prokaryotes have cell walls surrounding their plasma membranes and can be spherical, rod-like, or spiral in shape.

Evolution and Origin of Cells

Archaea thrive in extreme environments and share ancestral lineage with both bacteria and eukaryotes.
The mitochondrion likely originated from engulfed aerobic bacteria, playing a critical role in energy production.

Cellular Processes

Endocytosis is the process by which eukaryotic cells engulf external materials.
The Golgi apparatus modifies and packages molecules from the endoplasmic reticulum (ER) for secretion or transport.
Lysosomes are responsible for intracellular digestion, while peroxisomes facilitate reactions that neutralize toxins.

Organelles and Their Functions

The nucleus, surrounded by a nuclear envelope, contains DNA and is critical for cell regulation.
Chloroplasts carry out photosynthesis and have evolved from engulfed photosynthetic bacteria.
The endoplasmic reticulum serves as the site for synthesizing cell-membrane components and exported materials.

Cytoskeleton and Cellular Dynamics

The cytoskeleton facilitates cell movements and is composed of actin filaments, microtubules, and intermediate filaments.
Evidence suggests eukaryotic cells may have evolved as predators, requiring adaptability and complex features like a nuclear compartment.

Model Organisms in Research

E. coli serves as a model for molecular biology, aiding in understanding DNA replication and protein synthesis.
Brewer's yeast (Saccharomyces cerevisiae) is significant for studying eukaryotic cell tasks, particularly the cell cycle.
Arabidopsis thaliana is a model plant used for its rapid growth and relevance to agricultural research.

Fundamental Biological Principles

Life operates as an autocatalytic process, where DNA and RNA sequence information drives protein synthesis, which in turn facilitates the replication of nucleic acids.
The cell theory posits that all living cells arise from the division of existing cells, forming the foundation of biological understanding.### Model Organisms in Research
Arabidopsis thaliana: Serves as a model for studying plant genes; insights gained benefit our understanding of crop development, physiology, and the evolution of plant species.

Drosophila melanogaster (Fruit Fly)

Foundation of classical genetics research; crucial for understanding genetic influence on multicellular organism development.
Its genetic similarities to humans provide a platform for studying human development and the genetic underpinnings of diseases.

Caenorhabditis elegans (Nematode Worm)

Serves as a model for investigating developmental processes relevant to humans.
Research into its precise 959-cell development offers insights into apoptosis, enhancing understanding of programmed cell death.

Zebrafish

Transparent in early life stages, facilitating real-time observation of cellular behaviors during development.
Ideal for studying embryonic development in vivo due to clear visibility of internal processes.

Mouse

Key model organism for mammalian genetics, development, immunology, and cell biology.
Nearly all human genes have counterparts in mice, making them invaluable for researching human health and disease mechanisms.
Mice can be genetically modified to analyze specific gene functions through breeding and mutation.

Human Cells

Many human cell types can be cultured outside the body, allowing for the study of their behavior and properties in a controlled environment.
Culturing enables exploration of cellular functions that may not be achievable in living organisms.

Electron Microscopy

Transmission Electron Microscopy (TEM): Generates 2D images, ideal for viewing detailed internal structures in specimens.
Scanning Electron Microscopy (SEM): Produces 3D images, providing surface details and topography of objects, enhancing visualization of complex structures.

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Description

Explore key concepts from Biology Chapter 1 with these informative flashcards. Test your understanding of processes like transcription and translation, and the central dogma of molecular biology. Perfect for students aiming to solidify their knowledge in genetics and cell biology.