b2.3 - cell specialisation

Question 1

diploid cells

Answer 1

containing 2 set of chromosomes (2n)

Question 2

morula

Answer 2

solid ball of cells (16-32) formed from divisions of zygote

Question 3

blastocyst

Answer 3

cluster of dividing cells formed by the fertilised egg

• hollow ball of cells

Question 4

trophoblast

Answer 4

• outer layer of blastocyst
• cells will become the placenta

Question 5

inner cell mass (ICM)

Answer 5

• cells within the blastocyst that will become the embryo

Question 6

This difference in gene expression is what determines the type of cell that is formed

Answer 6

yuh

Question 7

morphogen

Answer 7

form-giving molecules secreted by cells in early embryo

Question 8

enterocyte cells

Answer 8

• found on surface of villi, in intestines, absorbs nutrients

Question 9

increasing surface area in digestive system

Answer 9

• villi on surface of small intestine, enterocytes are found on the surface of villi, each have 600 microvilli

Question 10

increasing surface area in kidney

Answer 10

• proximal convoluted tubule has microvilli to absorb substances

Question 11

squamous type 1 pneumocytes

Answer 11

• thin cells in the lungs responsible for gas exchange
• reduces diffusion distances
• make up 95% of the alveolar surface

Question 12

type 2 pneumocytes

Answer 12

5% of the alveolar surface but outnumber the type I cells. They are cuboidal in shape, with the tip of the cell protruding into the alveolar space

• surface surfactant into alveolar space

Question 13

types of muscles (3)

Answer 13

• cardiac (cardiomyocytes)
• skeletal
• smooth

Question 14

cardiomyocytes

Answer 14

• 150 micrometres
• single nucleus
• many mitochondria
• branced fibres

Question 15

how are cardiomyocytes connected to each other

Answer 15

• branced fibres connects to neighboring cardiomyocytes by gap junctions & intercalated discs
• 3D

Question 16

skeletal muscles

Answer 16

• in bundles surrounded by connective tissues
• can be up to 12 cm
• unbranched
• many nuclei
• contain myofibrils (made of actin and myosin)

Question 17

largest human cell

Answer 17

egg cell

Question 18

list functions of proteins (provide examples)

Answer 18

transport (hemoglobin in oxygen transport)
contractile (actin and myosin in muscles)
defense (antibodies in immune)
hormonal (insulin to regulate blood sugars)

Question 19

reasons for cell division in living organisms

Answer 19

• growth and development
• repair and regeneration
• reproduction
• maintain SA:V
• genetic stability