Cell Biology Review Flashcards
What are the characteristics of living things?
Movement, respiration, sensitivity, growth, reproduction, excretion, and nutrition.
What are cells?
Cells are the smallest unit that can perform the functions of life.
How many cells are our bodies made up of?
10 trillion and 100 trillion cells.
What is the Cell Theory timeline?
Hooke 1665: Observed remains of dead plant cells.
Leeuwenhoek 1673: First to see a living cell using a simple microscope.
Schleiden 1838: All plants are made up of cells.
Schwann 1839: All animals are made of cells.
Virchow 1855: Reasoned that cells come from other cells.
How else do cells divide?
- Reproduction: Single-celled organisms, like yeast and bacteria, reproduce through cell division, creating daughter cells that are exact genetic copies of themselves.
- Growth: By the time you were born, most of your body’s cells had already developed into specialized types. These cells divide and expand as you grow. Every person, including you, began as a single cell (zygote) and developed through cell division and specialization.
- Repair: Cell division helps repair injuries, like a cut, and fights infections. For example, bone marrow produces immune cells to combat infections and generate new cells for healing broken bones.
What is the Cell Theory?
- All living things are made up of one or more cells.
- The cell is the simplest unit that can carry out all life functions.
- All cells come from pre-existing cells.
What are prokaryotes?
Simple, single celled organisms. Their cells do not contain a nucleus or other membrane bound organelles, like bacteria.
What are eukaryotes?
Complex single-celled or multicellular organisms. Their cells contain a nucleus and other organelles, each surrounded by a thin membrane, like plants, animals, fungi, and protists.
What are some common misconceptions about cells?
- All animal cells are circular and all plant cells are rectangular.
- Cells differ widely in terms of shape. - All animal and/or plant cells are identical in terms of structure. For example, all cells contain a nucleus.
- Red blood cells are enc
What are organelles?
Cell structures that perform a specific function for the cell. They can be membrane-bound (surrounded by a membrane) or not.
What special functions do the cell’s organelles have in maintaining all the life processes of the cell?
Intake of nutrients, response to stimuli, movement, growth, exchange of gases, reproduction, and waste removal.
What are the parts of an animal cell?
Nucleus, nucleolus, cell membrane, cytoplasm, mitochondria, ribosomes, lysosomes, vesicles, endoplasmic reticulum, chromatin, and cytoskeleton.
What is the cell membrane (gatekeeper) and what is its function?
The cell membrane is the outer covering of the cell that forms a protective barrier around it. The cell membrane is designed to allow different substances to move through it.
What are ribosomes (assembly line workers) and what are their functions?
Ribosomes are small spherical sturctures that can be free-floating in the cytoplasm or attached to ER. Their function is to make proteins.
What are the two types of ER?
Smooth and rough (with ribosomes attached).
What is the mitochondria (powerhouse of the cell) and what is its function?
Mitochondria is a bean-shaped organelle that contains many cells. It makes energy for the cell’s activities.
What is the nucleus (brain) and what is its function?
The nucleus is the control center organelle of the cell as it controls all the activities in a cell, including growth and reproduction. The nucleus contains all of the cell’s DNA.
What is the nucleolus (factory) and what is its function?
The nucleolus (also known as “little nucleus”) is the dense structure in the nucleus. Its function is to make ribosomes.
What are golgi bodies (Fed Ex) and what are its functions?
Golgi bodies receive proteins from the endoplasmic reticulum. Their function is to modify, sort, and package proteins, lipids, and carbohydrates, into small vesicles for delivery to targeted destinations.
What are vesicles (mail) and what is their function?
Vesicles are single layer membranes that enclose fluids in a sac. Their purpose is to store and/or transport materials.
What is the cytoplasm (river/ground) and what are its functions?
The cytoplasm is a jelly-like substance that fills the cell and surrounds the organelles. Cytoplasm contains the nutrients required by the cell to carry on its life processes. The physical nature of the cytoplasm allows the nutrients and organelles to move within the cell.
What are lysosomes (Lysol/cleaner) and what is its function?
Lysosomes are small organelles that are filled with enzymes, where digestion takes place. They also break down invading bacteria and damaged cell organelles.
What is the endoplasmic reticulum, aka ER (conveyor belt) and what are its functions?
The endoplasmic reticulum are tubes that branch into cytoplasm and are near/around the nucleus. It transports materials throughout the cell as ribosomes are attached to the outside.
What is the chromosome/chromatin (blueprint) and what is its function?
The chromosome/chromatin contains DNA that is “loose”/unwound as it is in the nucleus.
What is the cytoskeleton?
The cytoskeleton, which is made up of protein filaments, is when all cells have an internal network of fibres. It helps maintain the cell’s shape.
What are centrioles?
An organelle that helps cells divide or make copies of themselves.
What are the parts of a plant cell?
Cell wall, cell membrane, plasma membrane, chloroplast, large central vacuole, ribosomes, mitochondria, nucleus, golgi apparatus, cytoplasm, endoplasmic reticulum, and peroxisomes.
What is the cell wall (cell plant) and what are its functions?
The cell wall is made of cellulose and is only found in plants. Its functions are to protect and provide support, while also giving the cell rigid shape.
What are chloroplasts (solar panels) and what are their functions?
Chloroplasts are only in plants and have their own DNA. Their functions are to absorb sunlight, so plants can make oxygen + glucose in a process called photosynthesis.
What is the large central vacuole (warehouse) and what is its function?
The vacuole is a fluid-filled sac in the cytoplasm that is much larger in plant cells. Its function is to store water, food and waste, starch and other materials. It also supports the cell.
What is the same of animal and plant cells?
Unlike animal cells, plant cells have chloroplasts, a cell wall, and a large central vacuole. Unlike plant cells, animal cells have centrioles.
What are peroxisomes (processing plant) in the plant cell?
In plants, peroxisomes convert stored oils into molecules that can be used for energy.
What are the differences between animal and plant cells?
Unlike animal cells, plant cells have chloroplasts, a cell wall, and a large central vacuole. Unlike plant cells, animal cells have centrioles.
What are light microscopes used for?
To view cells and tissues.
What are electron microscopes used for?
To view molecules and very tiny organelles.
What do modern microscopes used for?
Making cells, bacteria, and microorganisms viewable by humans.
Why do we use microscopes?
To magnify organisms /cells that are too small to see with the naked eye.
What is a compound microscope?
A microscope with two or more lenses and a light source to magnify objects.
What is magnification?
The ratio of an object’s image to its real size.
How do you calculate magnification?
Magnification = Eyepiece X Objective Lens
What is the function of the ocular lens (eye piece)?
It contains a magnifying lens and is fitted to the body tube. It magnifies objects by 10x.
What is the function of the body tube?
It supports the objective lenses.
What is the function of the revolving nosepiece?
It’s a disc-shaped piece at the lower end of the body tube, which rotates, allowing the objective lenses to be changed.
What is the function of the objective lenses?
It magnifies the object.
What is the function of the low power objective lenses?
It magnifies objects 4x. When combined with a 10x ocular lens, gives a magnification of 40x.
What is the function of the medium power objective lens?
It magnifies objects 40x. When combined with a 10x ocular lens, it gives a magnification of 400x.
What is the function of the high power objective lenses?
What is the function of the stage?
The part that supports the microscope slide.
What is the function of the stage clips?
It holds the slide onto the stage.
What is the function of the condenser lens?
It focuses the light onto the specimen.
What is the function of the diaphragm?
It regulates the amount of light reaching the specimen.
What is the function of the light source?
It shines light through the specimen.
What is the function of the base?
It supports all parts of the microscope.
What is the function of the arm?
It has curved support and is the area you pick up the microscope with.
What is the function of the coarse adjustment knob?
It is used to bring an object to view (Used with low power objective only).
What is the function of the fine adjustment knob?
Brings specimens into sharp focus under medium and high power. Used only after the object has been located and focused under low power.
How do you take care and use a microscope?
- Carry the microscope using two hands (at the arm and base).
- Plug in and check that the light works.
- Obtain or create a slide and place it on the stage.
- Check that the objective is low power (4x).
- Check the diaphragm (open to largest size) = max light.
- Focus using the coarse adjustment knob at low power (4x).
- Switch to medium power (10x) and use the fine adjustment knob only.
- If needed, switch to high power and use only the fine adjustment.
- Remove the slide after sketching and labeling the diagram.
- Calculate magnification.
- When returning microscope, you should:
- Turn light off.
- Change to low objective lens.
- Lower the stage
- Wrap the cord around the base.
What is diffusion?
When molecules move from an area with a high concentration to molecules to an area with a low concentration of low molecules.
When will diffusion continue?
Until equilibrium is reached.
What is osmosis?
When water molecules move from an area with a high concentration of water molecules to an area with a low concentration of water molecules.
Why must cells work together?
In order to keep us alive.
How do cells work together in order to keep people alive?
By having a selective permeable cell membrane.
What does this mean for the cell membrane?
That only certain types of ions and molecules can pass through the cell membrane.
What does the cell membrane do for the cell?
To regulate what goes and what comes out of the cell.
What are the three types of osmosis?
Hypotonic Solution, Hypertonic Solution, and Isotonic Solution.
How would you describe Hypotonic Solution?
There is less solute in the cell, there is high concentration of solutes and low concentration of H2O inside the cell, water moves into the cell, and the “cell swells”.
How would you describe Hypertonic Solution?
There is more solute outside of the cell, low concentration of solute and high concentration of H2O inside the cell, H20 moves out of the cell, and the “cell shrivels”.
How would you describe Isotonic Solution?
There is equal concentration of solute and inside, H2O moves in and out in equal amounts.
Why do cells divide?
Your body constantly renews certain cells, like those in your skin and in your blood. Skin cells dry out and shed, while blood cells lose efficiency and are replaced roughly every 100 days. This ongoing process ensures your skin and circulatory system stay healthy, which is why the tissues that create these cells keep dividing.
What is the Cell Cycle?
The entire life span of the cell.
What are the two processes by which cells divide?
Mitosis and meiosis as these phases are only part of the entire cell cycle.
What are body cells made up of?
46 chromosomes, which divide into 2 identical daughter cells and each have 46 chromosomes.
What are sex cells made up of?
46 chromosomes, which divide into 2 gametes (sperm or egg cell) and each have 23 chromosomes.
What are chromosomes?
The genetic information (DNA) in cells, and stored in the nucleus.
What is DNA in the form of during Interphase?
Chromatin, which is unwound DNA.
Before mitosis, what happens when cells divide?
DNA condenses into a chromosome.
What is mitosis?
When the nucleus duplicates.
What are the two stages of mitosis?
Stage 1: Nuclear division (4 phases in this stage).
Stage 2: Cytokinesis (Division of the rest of the cell.
What does each cell division produce?
Two genetically identical daughter cells.
What is mitosis?
When the nucleus duplicates.
What is Interphase?
When the cell is growing and the DNA is replicated in the nucleus (chromosomes double) towards the end.
What are the five stages of mitosis?
Prophase, Metaphase, Anaphase, Telophase, and Cytokinesis.
What is Prophase?
When the nuclear membrane is dissolving and centrioles move to opposite poles.
What is Metaphase?
When the double stranded chromosomes all line up the middle of the cell and the nuclear membrane is dissolved.
What is Anaphase?
When centrometers split and spindle fibres pull chromosomes to opposite ends of the cell.
What is Telophase?
When cells are splitting, chromosomes become chromatin (because they are thin and no longer visible), the nuclear membrane reappears, and the cell appears to have 2 nuclei.
What is Cytokinesis?
After mitosis, cytoplasm and organelles split up evenly and split into 2 daughter cells (identical to parent cell).
What is the disadvantage for having mitosis and cytokinesis being the means of reproduction?
Lack of diversity (identical daughter cells): Since only the traits of one parent are passed onto offspring, all of them are identical in every way. This leads to a lack of diversity among the population.
What happens during the cell cycle?
The cell’s activities are controlled at specific points.
What do specialized proteins do?
Send messages to the nucleus, which instructs the cell whether to divide or not.
Why won’t a cell divide?
Unless signals from surrounding cells tell the cell not to divide, there aren’t enough nutrients for cell growth, DNA within the nucleus has not been replicated, or if the DNA is damaged.
Why is the Cell Cycle a vital process?
Because it helps keep organisms healthy.
How do cancer cells work?
They undergo mitosis uncontrollably and develop when the cell’s DNA is changed through mutation. DNA prevents the cell from staying in Interphase for the normal period of time. This can be caused by environmental factors or viruses.
What is a tumor?
When a rapidly growing lump appears on your skin due to uncontrollable growth.
What are the two types of tumors?
Benign, which generally does not affect surrounding cells and malignant, which is cancerous.
What is metastasis?
The spread of cancer cells from the place where they first formed to another part of the body.
What causes cancer?
Cancer is caused by mutations, which are a random change in the DNA. Some mutations are caused by carcinogens (environmental factors), such as tobacco, radiation (X-rays and UV rays), and chemicals.
What have Health Canada reports indicated?
That 9 out of 10 lung cancer cases are caused by smoking.
What are some factors affecting a person’s risk of getting cancer?
- Personal medical history
- Heredity (breast and colon cancer)
- Exposure to carcinogens in the environment
- Lifestyle choices: exercise and food choices
When do you do cancer screening?
- At home, as part of a routine self-examination.
- By a doctor, such as a pap test or blood test.
- As genetic testing, when there is a family history of cancer.
What does screening increase the chance of?
Detecting cancer early enough to successfully treat it.
What are five ways to diagnose cancer?
Endoscopy, MRI, X-ray, ultrasound, and CT scanning.
How do you treat cancer?
By performing surgery, chemotherapy, and radiation therapy.
What does surgery do to take care of cancer?
It’s the physical removal of tumor.
What does chemotherapy do to take care of cancer?
Drugs spread through the body to stop cancer cells from dividing as they ‘kill’ cancer cells so that they can damage healthy cells.
What does radiation therapy do to take care of cancer?
Radiation damages DNA. Beams of radiation are directed at tumor, or radioactive sources are surgically implanted in tumor.
How is the behavior of cancer cells different from that of normal cells?
By ignoring signals that control growth and division, leading to proliferation (rapid reproduction of a cell, part, or organism), invasion of tissues, and metastasis (spreading).
What is a carcinogen?
Any substance, organism, or agent capable of causing cancer, including things like chemicals, radiation, viruses, and certain lifestyle factors.
Give some examples of carcinogen that may be present in your everyday life.
Tobacco smoke, alcohol, processed meats, and ultraviolet radiation (UV).
Why might it be easy to overlook cancer in its early stages?
Symptoms might be subtle, mimic other conditions, or be absent altogether, and people may delay seeking medical attention due to fear or lack of awareness.
Why might a doctor be concerned about finding cancer cells in a patient’s blood?
It suggests the cancer may have spread (metastasized) to other parts of the body, or that the patient may have a blood cancer like leukemia, requiring immediate attention and treatment.
Why might there be a risk of cancer recurring, even when surgery is performed to remove a malignant tumor?
Microscopic cancer cells may remain in the body, spread to other areas, or because the cancer cells may evolve and become resistant to treatment.
What is apoptosis?
A form of cell death that is triggered by normal, healthy processes in the body.
What is necrosis?
A form of cell death that is triggered by external factors, such as trauma or infection.
What are stem cells?
Unspecialized cells that can divide to form specialized cells.
What happens to stem cells during development?
Stem cells can receive special signals from their genetic information and begin to divide and specialize.
What are the two types of stem cells?
Embryonic stem cells and adult stem cells.
What are embryonic stem cells?
They can receive signals to develop into any kind of cell.
What are adult stem cells?
They can only be differentiated into certain types of cells.
What happens to stem cells when it comes to differentiation?
Differentiation occurs when cells get signals to develop in different ways. The cell can only receive signals when it is in Interphase. These cells will start to look different from one another and perform different functions.
How many specialized cells are in the human body?
200 specialized cells.
What is a specialized cell?
A cell that can perform a specific function. Each specialized cell has a unique shape, size and features allowing it to do its job accurately.
What do the different physical and chemical properties in specialized cells allow them to do?
Perform one job very well.
What is the description and function of red blood cells?
Description: Smooth and donut-shaped, so that they can easily pass through blood vessels.
Function: Contain hemoglobin that carries oxygen from the lungs to other cells in the body.
What is the description and function of muscle cells?
Description: Arranged in bundles called muscle fibres.
Function: Work together to contract, which causes things to move.
What is the description and function of nerve cells?
Description: Long, threadlike branches.
Function: Conduct electrical impulses.
What is the description and function of skin cells?
Description: Fit together tightly, covering the outside of the body.
Function: Fit together tightly in layers to protect cells inside and reduce water loss.
What is the description and function of fat cells?
Description: Stores chemical energy in the form of lipids.
Function: Have large vacuoles to store fat molecules. This is how the cell stores chemical energy.
What is the description and function of white blood cells?
Description: Can move itself like an amoeba.
Function: Engulfs bacteria and fights infection.
What is the description and function of bone cells?
Description: Collects calcium from food.
Function: To grow and repair bones, support the body and muscles.
What is the description and function of epidermal cells (in plants)?
Description: Have hairs on young roots.
Function: The hairs absorb water from the soil.
What is the function of sperm cells?
Carries DNA to female egg cell.
What is the function of photosynthetic cells?
Contain many chloroplasts to collect energy from the sun to make the sugar for the plant.
Which specialized cell has no nucleus and never undergoes mitosis?
Red blood cells.
Which specialized cell has long, skinny arms to send messages quickly over long distances?
Nerve cells.
Which specialized cell contains many mitochondria?
Muscle cells.
Why are complex organisms made up of specialized cells?
To perform diverse and efficient functions, enabling them to develop complex structures and systems and maintain internal balance (homeostasis).
What is the advantage of treating specialized cells to make them behave as stem cells?
To regenerate and repair tissues that have been damaged or affected by disease.
What is one advantage and one disadvantage of having a body made mostly of specialized cells rather than a body made of one type of cell that performs many functions?
An advantage is that having a body composed mainly of specialized cells is increased efficiency and complexity, allowing for diverse and complex functions. However, a disadvantage is that the body becomes highly dependent on the coordinated function of these specialized cells, and damage to one type can have widespread consequences.
What is regeneration?
Regeneration occurs when a body part is replaced and regrown.
Which animals are known to regenerate?
Salamanders, starfish, and some reptiles are known to do this.
Regeneration happens because of what?
Mitosis and stem cells.
What happens when cells in the region where the new limb starts to grow?
They will start dividing and specializing.
