Cell Biology and Techniques Quiz

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Questions and Answers

What is the main purpose of a Scanning Electron Microscope?

To identify different types of cells

To study the structure of atoms

To produce a three-dimensional image of a specimen (correct)

To magnify cells up to 300,000 times

Which of the following techniques was used to determine the structure of DNA as a double helix?

Atomic Force Microscope (AFM)

Fluorescent Antibody Technique

Scanning Tunnelling Microscope (STM)

X-ray Crystallography (correct)

The Human Genome Project focused on mapping all human chromosomes. What were the two main objectives of this project?

Identifying the location and function of all human genes (correct)

Understanding the role of DNA in cell division

Creating new varieties of medicine for treating diseases

Developing new drought-resistant plants

What is the significance of the Fluorescent Antibody Technique in cell research?

It helped prove that cells are open systems, constantly interacting with their environment (C) Signup and view all the answers

What is the main advantage of using GFP technology in cell research?

It can be used to identify specific proteins in cells. (A) Signup and view all the answers

Which of the following is NOT a characteristic of a prokaryotic cell?

They have specialized organelles (D) Signup and view all the answers

What is the most significant contribution of gene mapping to our understanding of inheritance?

It demonstrated the importance of DNA in cell function (A) Signup and view all the answers

Which statement best describes the role of organelles in a cell?

They are tiny organs that carry out specific functions within a cell (A) Signup and view all the answers

What is the primary function of the semi-permeable membrane in hemodialysis?

To filter out waste products from the blood. (B) Signup and view all the answers

Why is it essential for cells to maintain a high surface area-to-volume ratio?

To ensure sufficient nutrient uptake and waste removal. (D) Signup and view all the answers

In the Starch-Glucose test, what would you expect to happen to the concentration of glucose inside the dialysis tubing?

Glucose concentration will increase inside the tubing. (D) Signup and view all the answers

How does the structure of the alveoli in the lungs contribute to efficient gas exchange?

Alveoli provide a large surface area for diffusion of gases. (B) Signup and view all the answers

Which of the following scenarios demonstrates the principle of a high surface area-to-volume ratio?

A large, flat sheet of paper absorbs water more quickly than a crumpled ball of paper. (D) Signup and view all the answers

Which of the following is NOT a type of passive transport?

Endocytosis (A) Signup and view all the answers

How is diffusion involved in the process of how plants get nutrients from the soil?

Nutrients diffuse from an area of high concentration in the soil to an area of low concentration in the plant roots. (B) Signup and view all the answers

What is the primary function of dialysis tubing in the context of cell transport?

To mimic the function of a cell membrane by allowing the passage of certain molecules and blocking others. (C) Signup and view all the answers

Which of the following factors will NOT increase the rate of diffusion?

Increasing the size of the molecules (B) Signup and view all the answers

Which of the following is considered a passive form of transport across a cell membrane?

Facilitated diffusion (A) Signup and view all the answers

Which of the following is NOT a characteristic of passive transport?

Requires energy (B) Signup and view all the answers

What is the role of a concentration gradient in passive transport?

It determines the direction of movement of molecules from an area of high concentration to an area of low concentration. (C) Signup and view all the answers

Which of the following statements accurately describes the process of osmosis?

The movement of water molecules across a semi-permeable membrane from an area of high water concentration to low water concentration. (B) Signup and view all the answers

Which of the following statements accurately describes the role of the cuticle in plant protection?

The cuticle is a waxy substance secreted by cells that reduces water loss and protects the plant. (A) Signup and view all the answers

Which of the following best describes the function of the root system in plants?

To transport water and dissolved minerals from the soil to the rest of the plant. (D) Signup and view all the answers

What is the primary function of the shoot system in plants?

To produce flowers, fruits, and seeds for reproduction. (B) Signup and view all the answers

Which of the following accurately describes the process of plant growth?

Plant growth is the result of cell division in the meristem region, which occurs at the tips of leaves. (D) Signup and view all the answers

What is the main function of xylem in plants?

To move water and dissolved minerals from the roots to the leaves. (C) Signup and view all the answers

What type of tissue is responsible for protecting a plant from disease and environmental factors?

Dermal tissue (A) Signup and view all the answers

What is the function of the phloem in plants?

To transport sugars from the leaves to the roots. (D) Signup and view all the answers

Which of the following is an example of a plant organ system?

Shoot system (D) Signup and view all the answers

What is the primary role of phloem in plants?

Transport of dissolved sugars from leaves (A) Signup and view all the answers

Which cells are responsible for controlling sugar transport within the phloem?

Companion cells (A) Signup and view all the answers

What is NOT a function of ground tissue in plants?

Gas exchange in stomata (D) Signup and view all the answers

Where does the majority of photosynthesis take place in a plant?

In the palisade cells (B) Signup and view all the answers

What is the role of guard cells in plant physiology?

Control gas exchange through stomata (A) Signup and view all the answers

What was the manipulated variable in Francesco Redi's experiment?

Cover of the jars (A) Signup and view all the answers

What was the outcome of Redi's experiment regarding maggots?

Maggots were found only in the jar open to air (A) Signup and view all the answers

Needham's experiment suggested that which of the following was true about microorganisms?

Boiling destroys all microorganisms (D) Signup and view all the answers

What was Spallanzani's hypothesis regarding the source of microorganisms in his experiments?

They came from the air inside the flask (B) Signup and view all the answers

What was the main purpose of Pasteur's S-shaped flask experiment?

To prevent dust and microbes from reaching the broth (C) Signup and view all the answers

Who is credited with coining the term 'cells' when observing cork under a microscope?

Robert Hooke (C) Signup and view all the answers

Which statement about cell theory is true?

It excludes viruses and prions (C) Signup and view all the answers

What was Aristotle's contribution to early biological science?

He developed the scientific method by observing animal species (C) Signup and view all the answers

Signup and view all the answers

Study Notes

Microscopy

Microscopes magnify objects, making them appear larger than they are. This allows observation of objects too small to be seen with the naked eye.
There are two basic types of microscopes: simple and compound.
Simple microscopes are early types, consisting of a single lens, such as a magnifying glass.
Compound microscopes, which contain more than one lens, are parfocal(still focused when objectives are switched). Research microscopes use transmitted light, creating an inverted image and commonly magnify up to 400X, ideal for transparent specimens. Dissecting microscopes are parfocal and have a single objective that allows for a virtual image (same as the actual object) useful with solid objects and magnification up to 30X.
Parts of a microscope include: Ocular (magnifies 10X), Objective Lenses (vary in magnification: low 4x, medium 10x, high 40x), Revolving Nosepiece (holds objectives), Course Focusing Knob(focuses the object on low power), Fine Focusing Knob(clears image), Iris Diaphragm (regulates light), Light Source.

The Cell Theory

Early humans were unable to explain how life arose. Early scientists and doctors had theories about life appearing out of non-living materials.
Spontaneous generation stated that life could arise from non-living matter. This theory was disproven by Francesco Redi (1668) and Louis Pasteur (1864) through experiments using sealed vessels.
The Cell Theory applies to all living things, except prions & viruses. It is fundamental to biology, beginning with the observations of Aristotle, Robert Hooke (1665, who coined the term "cell"), and Antoni van Leeuwenhoek.

Cell Theory details.

The Cell Theory states that
1. All living things are made of one or more cells and/or substances produced by these cells.
2. All life functions take place within the cell, making them the smallest unit of life.
3. All cells are produced by the division of pre-existing cells.

Imaging and Staining Techniques

Microscope observation is affected by contrast (showing differences between structures) and resolution (showing detail). Contrast can be improved with staining techniques (e.g., iodine, methylene blue).
New technologies allow improved imaging in research, like fluorescence microscopy, which uses ultraviolet light for glowing samples, or confocal technology for 3-D images or electron microscopes. Electron microscopes use beams of electrons, with two types: Transmission Electron Microscopes (TEM) and Scanning Electron Microscopes (SEM). TEMs have a high magnification (up to 100,000 times). SEMs produce 3-D images in a vacuum, with a magnification up to 300,000.

Cell Research at the Molecular Level

Advances in technology, like Scanning Tunneling Microscopes (STM) and Atomic Force Microscopes (AFM), are used to image molecules.
Gene mapping using the Human Genome Project allowed understanding and mapping of the location and function of genes in chromosomes.
Biochemists & microbiologists showed that DNA contains genes which direct all cell activities and traits.

The Cell as an Efficient, Open System

Cells are open systems, exchanging matter and energy with their surroundings.
Cells acquire nutrients and excrete waste.
Cells carry out all life processes.
Two types of cells exist: prokaryotic cells (lack nuclei, DNA floats in cytoplasm, e.g., bacteria) and eukaryotic cells(have nuclei, DNA is packaged into chromosomes, e.g., plants, animals).

Cell Structures

The five main structures of a plant cell are: Cell wall (provides strength & support, found in plant cells, bacteria, and protists, made of cellulose), Cell membrane (protective barrier, semi-permeable, maintains balance or equilibrium), Nucleus (directs cellular activities, has DNA, a porous membrane & nucleolus), Cytoplasm (gel-like substance with organelles), and Organelles (tiny "organs" within the cell which have different functions).
Examples of organelles include: Mitochondria (site of cellular respiration), Endoplasmic Reticulum (smooth ER - site of fat/lipid & steroid production, rough ER - site of protein synthesis), Ribosomes (site of protein synthesis, take amino acids to make protein), Golgi Apparatus (stores proteins secreted outside the cell), Lysosomes (digest bacteria/damaged proteins, found in animal cells only, "suicide sac"), Vacuoles & Vesicles (storage of nutrients and water), Chloroplasts (site of photosynthesis).
Plant cells also have a rigid cell wall, and a large central vacuole for water storage.

Plant Transport

Plants transport water and nutrients from the roots to the leaves.
This process is aided by cohesion (attraction between water molecules-occurs because water is a polar molecule), adhesion (attraction between water and other substances-i.e. xylem wall), root pressure, and transpiration pull (water lost by evaporation through stomata, which pulls water up).
Plants have different tissues for gas exchange, including: dermal tissue which is the outermost layer (e.g. cuticle, stomata), ground tissue(inside the dermal tissue), vascular tissue which transports substances between the roots and shoots (xylem and phloem).

Plant Responses to Stimuli

Tropisms are responses that plants have to stimuli, such as light or gravity.
Phototropism is a plant's response to light, and it can be either positive (growing towards the light - e.g. leaves and stems) or negative (growing away from the light -e.g. roots).
Gravitropism is a plant's response to gravity, and positive gravitropism occurs when there is growth in the same direction as gravity (e.g.roots), whereas negative gravitropism occurs when there is growth in the opposite direction (e.g. stem).
Other factors which influence a plant's growth include temperature, touch (e.g. tendrils such as ivy). and length of daylight hours.

Other Applications

Membrane technologies are useful for creating liposomes for safer drug delivery and dialysis to remove waste from the blood when kidneys fail. There are two types of dialysis: peritoneal and hemodialysis.

Starch-Glucose & Iodine-Starch Tests

For the starch-glucose test, a solution of starch and glucose placed in dialysis tubing and then placed in water, may result in a color change as the substance diffuses, depending on the materials used for the test.
If an iodine-starch test uses a solution of starch and glucose placed in dialysis tubing and then immersed in a yellow iodine solution, the color change depends on the ability of the substances used in the test to pass through the semi-permeable membrane of the dialysis tubing.

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Description

Test your knowledge on key concepts in cell biology and microscopy techniques. This quiz covers essential topics such as the structure of DNA, the Human Genome Project, and various cell research methodologies. Challenge yourself with questions that explore the significance of organelles, membrane functions, and advancements in genetic research.