cell biology

Question 1

What type of cells have a nucleus and include animal and plant cells?

Answer 1

Eukaryotic cells

Eukaryotic cells are characterized by the presence of a nucleus, unlike prokaryotic cells.

Question 2

What controls the movement of substances into and out of a cell?

Answer 2

Cell membrane

The cell membrane is selectively permeable, allowing certain substances to pass while blocking others.

Question 3

What is the jelly-like substance where reactions take place inside a cell?

Answer 3

Cytoplasm

The cytoplasm contains organelles and is the site of many metabolic processes.

Question 4

Where does respiration take place in cells?

Answer 4

Mitochondria

Mitochondria are known as the powerhouse of the cell, where energy is produced.

Question 5

Where are proteins made inside a cell?

Answer 5

Ribosomes

Ribosomes can be found free in the cytoplasm or attached to the endoplasmic reticulum.

Question 6

What are cell walls made of that give a cell structure?

Answer 6

Cellulose

Cellulose is a complex carbohydrate that provides rigidity and structural support to plant cells.

Question 7

What stores cell sap and gives a cell structure?

Answer 7

Vacuole

Vacuoles are larger in plant cells and contribute to turgor pressure.

Question 8

What do chloroplasts contain that is used for photosynthesis?

Answer 8

Chlorophyll

Chlorophyll is essential for capturing light energy during photosynthesis.

Question 9

What absorbs light for photosynthesis?

Answer 9

Chlorophyll

Chlorophyll is a pigment found in chloroplasts that plays a crucial role in converting solar energy into chemical energy.

Question 10

Where is genetic material stored in a cell?

Answer 10

Chromosomes in the nucleus

Chromosomes are structures that carry genetic information and are composed of DNA.

Question 11

What type of cells are bacteria cells that have a cell membrane and cytoplasm but no nucleus?

Answer 11

Prokaryotic cells

Prokaryotic cells are simpler and smaller than eukaryotic cells.

Question 12

What happens as a cell differentiates?

Answer 12

It develops different sub-cellular structures to enable it to carry out a particular function.

This process results in specialized cells tailored for specific tasks.

Question 13

What are sperm cells specialized for?

Answer 13

Energy production with a large number of mitochondria

Mitochondria provide the energy needed for the movement of sperm.

Question 14

What are mesophyll cells specialized for?

Answer 14

Photosynthesis with a large number of chloroplasts

Mesophyll cells are found in plant leaves and are crucial for capturing light energy.

Question 15

When do animal cells differentiate?

Answer 15

At an early stage of life

This early differentiation is important for developing various tissues and organs.

Question 16

When can plant cells differentiate?

Answer 16

Throughout their life

This ability allows plants to adapt and grow in response to their environment.

Question 17

What is the formula for magnification?

Answer 17

Magnification = image size ÷ actual size

This formula helps determine how much larger an image appears compared to its actual size.

Question 18

What does µm stand for?

Answer 18

Micrometre

A micrometre is one millionth of a meter, often used to measure cells.

Question 19

What does nm stand for?

Answer 19

Nanometre

A nanometre is one billionth of a meter, used to measure very small structures.

Question 20

How many micrometres are in 1 millimetre?

Answer 20

1000 µm

This conversion is useful for understanding measurements in microscopy.

Question 21

Which type of microscope was developed first?

Answer 21

Light microscopes

Light microscopes use visible light to magnify samples and were the first type of microscope used.

Question 22

What type of microscopes give greater magnification and resolution?

Answer 22

Electron microscopes

Electron microscopes use electron beams to achieve much higher magnifications than light microscopes.

Question 23

What process allows cells to divide for growth, repair, and development of an embryo?

Answer 23

Mitosis

Mitosis is a type of cell division that produces two genetically identical daughter cells.

Question 24

What are the three stages of the cell cycle?

Answer 24

1. DNA is copied & number of subcellular structures, mitochondria & ribosomes are increased
2. Chromosomes are pulled to either end of the cell and nucleus divides
3. Cytoplasm and cell membranes divide to form 2 genetically identical cells

Each stage is crucial for proper cell division and function.

Question 25

What are stem cells?

Answer 25

Undifferentiated cells found in embryos, adult animals, and meristems in plants ## Footnote Stem cells have the potential to differentiate into various cell types.

Question 26

What can stem cells from human embryos be cloned and made to differentiate into?

Answer 26

Most different types of human cells ## Footnote This capability holds promise for regenerative medicine.

Question 27

What treatments can stem cells be used for?

Answer 27

Diabetes and paralysis ## Footnote Stem cell therapy is being researched for various medical conditions.

Question 28

What are some risks associated with the use of stem cells?

Answer 28

Transfer of viral infection and religious and ethical objections about killing a potential human life ## Footnote These concerns are important considerations in the use of stem cells in research and therapy.

Question 29

How can stem cells in plants be used?

Answer 29

To produce clones of plants quickly and economically ## Footnote This technique is valuable for agriculture and horticulture.

Question 30

What is diffusion?

Answer 30

The passive movement of particles from a high concentration to a low concentration ## Footnote Diffusion is a fundamental process for the transport of substances in cells.

Question 31

What factors can change the rate of diffusion?

Answer 31

Concentration gradient, temperature, and surface area ## Footnote These factors influence how quickly substances move across membranes.

Question 32

What do multicellular organisms have that are specialized for exchanging materials?

Answer 32

Surfaces and organ systems ## Footnote These adaptations enhance the efficiency of material exchange.

Question 33

How can the effectiveness of an exchange surface be increased?

Answer 33

1. Having a large surface area 2. Thin membrane 3. Efficient blood supply (in animals) 4. Being ventilated (in animals for gas exchange) ## Footnote These features facilitate better exchange of gases and nutrients.

Question 34

What is osmosis?

Answer 34

The passive movement of water from an area of higher water concentration to an area of lower water concentration, across a partially permeable membrane ## Footnote Osmosis is crucial for maintaining cell turgor and overall homeostasis.

Question 35

What causes mass changes in plant cells?

Answer 35

The movement of water across a plant cell membrane ## Footnote This movement affects the cell's volume and pressure.

Question 36

What does active transport use to transport substances across a membrane?

Answer 36

Energy from respiration ## Footnote Active transport enables cells to move substances against their concentration gradient.

Question 37

Where is active transport used for the absorption of nutrients?

Answer 37

Root hair cells and the small intestine ## Footnote Active transport is essential for nutrient uptake in both plants and animals.