Cell biology

Question 1

The specific function specialised cells carry out

Answer 1

Most types of animal cell differentiate at an early stage.

• Many types of plant cells retain the ability to differentiate throughout life.

Question 2

In mature animals what are cells used for?

Answer 2

To répare and replace

Question 3

Name all the cells in an animal cell?

Answer 3

.cytoplasm
.a nucleus
.cell membrane
.mitrochondria
.ribosomes

Question 4

What do plant cells have that animal cells do not?

Answer 4

Chloroplast

a permanent vacuole filled with cell sap.

Question 5

What function do specialised cells give out?

Answer 5

• sperm cells, nerve cells and muscle cells in animals

• root hair cells, xylem and phloem cells in plants.

Question 6

As an organism develops, cells differentiate to form?

Answer 6

different types of cells.

Question 7

In mature animals, cell division is mainly restricted to

Answer 7

repair and replacement.

Question 8

An electron microscope has

Answer 8

much higher magnification and resolving power than a light microscope.

Question 9

What enables biologists to see and understand many more sub-cellular structures.

Answer 9

Electron microscopes

Question 10

How to calculate magnification

Answer 10

size of image size / of real object

Question 11

Bacteria multiply by simple cell division as often as?

Answer 11

Once every 20 minutes if they have the right amount of nutrients and have a suitable temperature

Question 12

Bacteria can be grown in a?

Answer 12

Broth solution, or as colonies on a agar bar plate

Question 13

Nucleus of a cell contains?

Answer 13

chromosomes made of DNA molecules.

Question 14

In body cells the chromosomes are normally found…

Answer 14

In pairs

Question 15

The first step of the cell cycle?

Answer 15

the genetic material is doubled and then divided into two identical cells.

Question 16

The second step in the cell cycle?

Answer 16

Before a cell can divide it needs to grow and increase the number of sub-cellular structures such as ribosomes and mitochondria. The DNA replicates to form two copies of each chromosome.

Question 17

What is the third step in the cell cycle?

Answer 17

In mitosis one set of chromosomes is pulled to each end of the cell and the nucleus divides.

Question 18

What is the fourth step of the cell cycle?

Answer 18

the cytoplasm and cell membranes divide to form two identical cells.

Question 19

A stem cell is?

Answer 19

an undifferentiated cell of an organism which is capable of giving rise to many more cells of the same type, and from which certain other cells can arise from differentiation.

Question 20

Stem cells from human embryos can be ?

Answer 20

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

Question 21

Stem cells from adult bone marrow can form?

Answer 21

many types of cells including blood cells

Question 22

Meristem tissue in plants can?

Answer 22

differentiate into any type of plant cell, throughout the life of the plant.

Question 23

Treatment with stem cells can help conditions such as?

Answer 23

Diabetes and paralysis

Question 24

What is therapeutic cloning?

Answer 24

It’s where an embryo is produced it’s the same genes as a patient. Stem cells from the embryo are not rejected by the patient’s body so they may be used for medical treatment.

Question 25

What are the risk of using stem cells?

Answer 25

Transfer viral infections/ some religions may object to it

Question 26

Why are stem cells useful for plants?

Answer 26

They can help them grow quicker. They can be cloned to become protected from extinction.

Question 27

Diffusion?

Answer 27

Where substances may move in and out of cell membrane.

Question 28

In further detail describe diffusion?

Answer 28

is the spreading out of the particles of any substance in solution, or particles of a gas, resulting in a net movement from an area of higher concentration to an area of lower concentration.

Question 29

What are some of the substances transported in and out of cells through diffusion?

Answer 29

Oxygen, carbon dioxide, gas exchange.

Question 30

What are the factors that affect the rate of diffusion

Answer 30

. The temperature . The surface area of the membrane . The difference in concentration

Question 31

What has a relatively large surface area to volume ratio, which allows sufficient transport of molecules into and out of the cell to meet the needs of the organism?

Answer 31

A single celled organism

Question 32

The effectiveness of an exchange surface is increased by:

Answer 32

Having a large surface area. A membrane that is thin, to provide a short diffusion path. Having an efficient blood supply.

Question 33

Define osmosis?

Answer 33

Osmosis is the diffusion of water from a dilute solution to a concentrated solution through a partially permeable membrane.

Question 34

Define active transport?

Answer 34

moves substances from a more dilute solution to a more concentrated solution (against a concentration gradient). This requires energy from respiration.

Question 35

How does active transport help plants absorb mineral ions?

Answer 35

By plant root hairs from very dilute solutions in the soil.

Question 36

Differentiation?

Answer 36

The process where unspecialised cells turn into specialised cells