2.2 Cell structure

Question 1

Cell differentiation

Answer 1

the process where cells become specialised by producing different proteins

Question 2

Cell membrane

Answer 2

a partially permeable barrier that surrounds the cell and controls which substances move in and out of cells

Question 3

cell wall

Answer 3

a fully permeable outer layer found in some cells
–> in plants it is made from cellulose
–> in fungi it is made from chitin

Question 4

Chloroplast

Answer 4

an organelle that is the site of photosynthesis

Question 5

Cytoplasm

Answer 5

contains dissolved nutrients and all of the organelles of the cell and the site of many metabolic reactions

Question 6

Mitochondria

Answer 6

an organelle that is the site of aerobic respiration

Question 7

Nucleus

Answer 7

an organelle found only in eukaryotic cells and contains the genetic material(DNA) and controls the activities of the cell

Question 8

Ribosomes

Answer 8

organelles that are the site of protein synthesis

Question 9

Stem cells

Answer 9

undifferentiated cell that can divide rapidly to produce specialised cells

Question 10

Vacuole

Answer 10

found in plant cells, contains dissolved nutrients and supports the shape of the cell

Question 11

What are the similarities in the structure of plant and animal cells?

Answer 11

both contain:
cytoplasm
nucleus
ribosome
mitochondria
cell membrane

both are multicellular

Question 12

What are the differences in the structure of plant and animal cells?

Answer 12

only plant cells contain:
chloroplast
vacuole
cell wall

plant cells are producers and photosynthesise to produce their own food and store cellulose in cell wall
animal cell eat other living things to obtain nutrients and store carbohydrates as glycogen

Question 13

What is the importance of cell differentiation in the development of specialised cells?

Answer 13

allows cells to specialize and perform specific functions in an organism

Question 14

What are the advantages of using adult stem cells in medicine?

Answer 14

supplied from the patients own bone marrow
no risk of rejection
large supply

Question 15

What are the disadvantages of using adult stem cells in medicine?

Answer 15

procedure of extracting from adult stem cells from bone marrow is painful
can only differentiate into white blood cells, red blood cells and platelets

Question 16

What are the advantages of using embryonic stem cells?

Answer 16

can differentiate into any type of specialised cell

Question 17

What are the disadvantages of using embryonic stem cells?

Answer 17

can be rejected by the immune system
raises ethical questions
limited supply
could begin uncontrollable cell division, which could lead to the formation of a tumour

Question 18

What is meat by the term differentiation?

Answer 18

differentiation is controlled by the genes
during differentiation, genes are switched off so that they cannot be transcribed
this ensures the only proteins produced in the specialised cell are the ones needed to carry out its particular job

Question 19

What are the two different types of stem cells?

Answer 19

embryonic stem cells
adult stem cells

Question 20

What is an embryonic stem cell?

Answer 20

embryonic stem cells are found in the early form of the embryo. They can differentiate into any type of cell.

Question 21

What is an adult stem cell?

Answer 21

Adult stem cells are present in some tissues in organisms
They divide by mitosis and each type of stem cell can differentiate into a few different types of specialised cell.
For example, bone marrow stem cells
can only form blood cells and bone cells.