Cell Biology Flashcards by Warsan Israr

What are examples of Eukaryotic cells?

Animal and plant ells, containing Cell membranes, Nuclei, Cytoplasm, Ribosomes, Mitochondria.

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What are some of the organelles specific to plant cells?

Cell wall, Chloroplasts, permanent vacuole.

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How do animal cells reproduce?

Mitosis: divide, grow to replace old cells.

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How do prokaryotic cells reproduce?

(bacteria) reproduce asexually.

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What are the differences between prokaryotic and eukaryotic cells?

-Prokaryotes much smaller in size.
- The genetic material in prokaryotes isn’t enclosed in a nucleus, there are rings of DNA (plasmids).
- Prokaryotes= unicellular.

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What are plasmids?

Rings of extra genes in prokaryotic cells

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What are the cell walls of plant cells made of?

Cellulose- strengths the structure of the cell.

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RP1: Describe the parts of a light microscope.

Eye piece lens, Objective lenses, Coarse + fine focus knobs, light source. Arm, base, body tube, stage.

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Describe how we can see the magnification through a light microscope.

-Light source causes light to pass through the slide.
-Light enters objective lenses, passes through and enters the eye.

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Define Image and Object.

Image- Picture we see when looking into microscope.
Object- Real thing we’re looking at (slide).

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Define magnification and resolution.

Magnification- How many times larger the image is than the object.
Resolution- How much detail can be seen.

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RP1: What are the differences between the electron and light microscopes.

Light- Cheap/ easy to use but resolution not good enough to see sub-cellular structures.
Electron- Expensive/ hard to use, 2000x better/ can see sub-cellular, resolution, rely on electrons.

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How do we calculate magnification?

Image size/ actual size= magnification.

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What is a specialized cell?

A cell which has differentiated and has specific shapes/structures to perform a specific role.

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Name 4 specialized cells.

Red blood cells, root hair, nerve cell and sperm cell.

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How have red blood cells adapted?

Biconcave shape- surface area, more absorption.
Thin membrane- gas diffuse easily.
Hemoglobin- Bind to oxygen.

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How have root hair cells adapted?

Long hair-like structures to inc. surface area.
Osmosis for water, Active transport for minerals.
Lots of mitochondria for energy for active transport.

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How have sperm cells adapted?

Flagella- Tail to swim to egg.
Streamlined- Swim
Lots of mitochondria- Energy to swim.

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How have nerve cells adapted to their function?

Myelin Sheath- Insulates the electric impulses that pass.

What is cell differentiation?

When a stem cell develops to become specialized.

What is the difference between differentiation in plants and in animals?

Plants cells- Retain the ability to differentiate.
Animal- Differentiate at an early stage.

Why is cell differentiation important?

Repair and replacement of mature cells.

What is a chromosome?

46 section of DNA, found in pairs in the nucleus to carry genes.

Why does the cell cycle need to occur?

Growth, development and repair. Young organisms- growth. Older organisms- repair/replacement.

What are the stages of mitosis?

Stage 1- GROWTH, Cell grows+ no. of subcellular structures, DNA replicates. Stage 2- MITOSIS, Copies of chromosomes pulled to ends. Stage 3- DIVISION, cytoplasm divides = 2 daughter cells.

What are the 2 features of stem cells?

Able to differentiate + can divide by mitosis.

Describe embryonic stem cells.

Cells of the embryo are called 'embryonic stem cells'. They are undifferentiated+ can differentiate into any type of cell.

Describe adult stem cells.

Found in bone marrow and can differentiate into some types of specialized cells.

Describe meristem tissue.

Found in the tips of roots and tips of shoots of plants. They live for years and retain the ability to differentiate.

What can stem cells be used for in medicine?

Type 1 diabetes- damage to pancreatic cells. Sickle cell anemia- Caused by misshape of red blood cells. Paralysis- Caused by damage to nerve cells.

How can stem cells be used to treat illnesses?

Extract stem cells, grow in lab, stimulate to differentiate into specific cell, give to patients to replace faulty cells.

What are some of the drawbacks of using stem cells in medicine?

Needs embryonic stem cells- Limited supply + some ethical issues. Rejection- the body may attack cells as they see it as foreign.

What are some of the risks of using stem cells in medicine?

Virus transmission. If stem cells divide too quickly, there could be risk of tumor development. May be rejected by patient.

What are some alternatives of using embryonic stem cells in medicine?

Using adult stem cells, however they can only differentiate into different types of blood cells.

What is therapeutic cloning?

An embryo with the same genes as the patient is used so its not rejected by the body.

Define diffusion.

The net movement of particles from areas of high concentration to low concentration.

What adaptations increase the rate of diffusion in cells?

Thin membrane, short diffusion path. An efficient blood supply, maintains conc. gradient.

What factors affect the rate of diffusion?

Concentration gradient Temperature Surface area

Define osmosis.

The net movement of water particles from an area of high concentration to an area of low concentration, through a partially permeable membrane.

If there is a high water concentration outside the cell, what happens to the cell.

It expands as water moves into the cell by osmosis.

RP3: Describe the method of testing the effects of osmosis on a plant.

1- Peel potato skin, use cork borer to produce three cylinders of potato. 2- Trim potatoes to equal lengths, measure masses using balance. 3- Place into different test tubes- distilled water, 0.25 and 0.5 molar sugar solutions. 4- Leave overnight. Gently, pat dry then weigh again. 5- Find percentage change.

What would be the results of placing potato cylinders in distilled water, 0.5 molar sugar solutions?

Distilled water- High concentration of water of outside, mass would increase. 0.5, higher water conc. in potato so water moves out and mass decreases.

Define active transport.

The net movement of particles from an area of low concentration to high through a membrane, requiring energy.

Why is active transport needed in plants.

Plants need water and mineral ions for proper growth- they get this from the soil. Root hair cells carry out active transport as there is a higher concentration of minerals inside the plant than in the soil.

How have root hair cells adapted to perform active transport?

Lots of mitochondria for energy from cellular respiration.

Give the conversion units of metres.

1,000,000,000 nm= 1m 1,000,000 micro= 1m 1000 milli= 1m 100 centi= 1m