Cell biology 4.1

Question 1

What is a characteristic of a eukaryotic cell?

Answer 1

DNA/genetic material enclosed in a nucleus

Question 2

What are 3 differences of eukaryotic and prokaryotic cells?

Answer 2

-Eukaryotic cells have genetic material enclosed in a nucleus

-Prokaryotic cells have genetic material in a single DNA loop called a plasmid

-Eukaryotic cells are bigger than prokaryotic cells

Question 3

Give 2 examples of eukaryotic cells

Answer 3

Plant and animal cells

Question 4

Give an example of a prokaryotic cell

Answer 4

Bacterial cell

Question 5

What are the sub-cellular structures of an animal cell?

Answer 5

Nucleus
Cytoplasm
Cell membrane
Mitochondria
Ribosomes

Question 6

What are the extra sub-cellular structures of a plant cell?

Answer 6

Chloroplasts
Permanent vacuole
Cell wall

Question 7

What are the functions of all the sub-cellular structures?

Answer 7

Nucleus- contains genetic material enclosed and controls the cells
Cytoplasm- site of most of the chemical reactions of the cell
Cell membrane- controls the movement of substances in and out of the cell
Mitochondria- site of respiration
Ribosomes- carry out protein synthesis
Cell wall- strengthen the cell
Permanent vacuole- filled with cell sap to keep cell turgid
Chloroplasts- contains chlorophyll for photosynthesis

Question 8

What are 3 specialised cells in animals?

Answer 8

Sperm cells, nerve cells and muscle cells

Question 9

What are 3 specialised cells in plants?

Answer 9

Root hair cells, xylem and phloem cells

Question 10

How are sperm cells, nerve cells and muscle cells specialised and what is their function?

Answer 10

Sperm: reach the egg
-lots of mitochondria to provide energy required to swim
- flagellum to help it swim
- enzymes to digest egg cell membrane

Muscle cells: contract
- lots of mitochondria to provide energy for the contracting
- protein filaments that slide over each other to cause the muscle to contract

Nerve cells: rapidly carrying electrical impulses around the body
- long axon to carry impulse long distances
-branched at both ends so they connect and pass signals between each other
-insulated in a fatty sheath which helps the impulse travel along the nerve cell faster

Question 11

When do most types of animal cells differentiate?

Answer 11

At an early stage e.g early stage embryo

Question 12

When can plant cells differentiate?

Answer 12

Throughout the plants life

Question 13

What happens when a cell differentiates?

Answer 13

Acquires different sub-cellular structures to enable it to carry out a different function

Question 14

What is a cell called once it has differentiated?

Answer 14

Specialised cell

Question 15

Whats the differences between light microscopes and electron microscopes?

Answer 15

Electron microscopes have a much higher resolution/resolving power and magnification than a light microscope so it can be used to study cells in more detail which has enabled biologists to see and understand many more sub-cellular structures

Question 16

Whats the equation for magnification?

Answer 16

Magnification = image size/actual size

Question 17

Whats the process that bacteria multiply by called?

Answer 17

Simple cell division (binary fission)

Question 18

How often do bacteria divide with optimal conditions?

Answer 18

Every 20 minutes

Question 19

What do bacterial colonies need to grow?

Answer 19

Enough nutrients and suitable temperature

Question 20

In what can bacterial colonies be grown?

Answer 20

In a nutrient broth or as colonies on agar gel plate

Question 21

How are chromosomes found in body cells? (Alone, in pairs, in threes…)

Answer 21

In pairs

Question 22

What are chromosomes made up of?

Answer 22

DNA molecules

Question 23

What is DNA made up of?

Answer 23

Genes

Question 24

What’s the series of stages called in cell division?

Answer 24

The cell cycle

Question 25

What occurs during the cell cycle?

Answer 25

Genetic material in a cell is doubled and then divided into 2 identical cells

Question 26

What occurs during the cell cycle?

Answer 26

1. Cell growth and duplication of sub-cellular structures and replication of DNA 2. One set of chromosomes is pulled to each end of the cell and the nucleus divides 3. Cytoplasm and cell membranes divide to form 2 identical cells

Question 27

Whats cell division by mitosis important for?

Answer 27

The growth and development of multi-cellular organisms

Question 28

Whats a stem cell?

Answer 28

An undifferentiated cell of an organism which can give rise to more cells of the same type and from which, certain other cells can arise through differentiation

Question 29

How can we use human embryo stem cells (general)?

Answer 29

Can be cloned and made to differentiate into most different types of human cells

Question 30

When and what can stem cells from meristem tissue differentiate into?

Answer 30

Any type of plant cell throughout the plants life

Question 31

What can stem cells from bone marrow differentiate into?

Answer 31

They can from many types of cells including blood cells

Question 32

What can stem cells he used to treat?

Answer 32

Diabetes and paralysis

Question 33

Whats a risk of using embryonic stem cells in therapeutic cloning?

Answer 33

Transfer of viral infection, some people have ethnic or religious objections

Question 34

What are advantages of therapeutic cloning of plants?

Answer 34

-Rare species can be cloned to be protected from extinction -crop plants with special features (e.g disease resistance) can be cloned to produce large numbers of identical plants for farmers

Question 35

Whats the process of therapeutic cloning in humans?

Answer 35

The process of producing an embryo with the same genes as the patient to make stem cells that aren’t rejected by the patient’s body and can therefore be used for medical treatment

Question 36

How do substances move in and out of cells?

Answer 36

Via diffusion

Question 37

What is diffusion?

Answer 37

The spreading out of particles in any substance in solution, or particles of a gas, resulting in a met movement from an area of higher concentration to and area of lower concentration

Question 38

What examples are there of diffusion in cells?

Answer 38

Oxygen and CO2 in gas exchange and urea from cells into blood plasma for excretion in kidneys

Question 39

What factors affect diffusion?

Answer 39

The concentration gradient The temperature Surface area (e.g of the membrane)

Question 40

What is the surface area:volume ratio like in a single-celled organism? What does this mean?

Answer 40

Large Allows sufficient transport of molecules into and out of the cell to meet the needs of the organism