module 2: cell division

Question 1

what is M phase

Answer 1

checkpoint

Question 2

what is the G1 checkpoint

Answer 2

checks chemicals needed for replication re present and checks for any damage before s-phase

Question 3

what is S phase

Answer 3

synthesis- cell replicates DNA

Question 4

what is G phase 2

Answer 4

cell grows and proteins made for division

Question 5

what is interphase

Answer 5

cells DNA unravelled and replicated, organelles are replicated and ATP content increases

Question 6

what is prophase

Answer 6

chromosomes condense, centrioles move to opposite ends of the cell and spindle fibres form, nuclear envelope breaks down

Question 7

what is metaphase

Answer 7

chromosomes line up on the equator of the cell and attach to spindle fibres

Question 8

what is anaphase

Answer 8

centromeres divide separating each pair of sister chromatids, spindle fibres contract pulling chromatids to opposite ends of the cell

Question 9

what is telophase

Answer 9

chromatids reach opposite ends of cell and they uncoil, they are then chromosomes again, nuclear envelopes form around each group of chromosomes so they are now 2 nuclei

Question 10

what can we use to observe the cell cycle

Answer 10

staining chromosomes

Question 11

what does meiosis produce

Answer 11

gametes for sexual reproduction, haploid and genetically different

Question 12

how does genetic variation occur

Answer 12

prophase 1- crossing over of chromatids, alleles are different combo
metaphase 1- lining up of chromosomes is random so daughter cells separate with different combinations of chromosomes

Question 13

what are stem cells

Answer 13

unspecialised cells that can differentiate into any type of cell

Question 14

where are stem cells found

Answer 14

early embryos, plant meristem, bone marrow

Question 15

what are stem cells used for

Answer 15

to replace damaged cells, specialise

Question 16

what are bone marrow cells used for

Answer 16

differentiate into blood cells

Question 17

what are meristem cells used for

Answer 17

differentiate into xylem and phloem

Question 18

what can stem cells cure

Answer 18

parkinsons, alzheimers

Question 19

what are neutrophils

Answer 19

flexible shape allows them too engulf pathogens, white blood cells, contain digestive enzymes

Question 20

what are erythrocytes

Answer 20

red blood cells, biconcave shape gives a large surface area, no nucleus so more room for haemoglobin

Question 21

what are epithelial cells

Answer 21

cover surface of organs, ciliated epithelial have cilia that wafter substances away, squamous are very thin to allow for efficient gas exchange

Question 22

what are sperm cells

Answer 22

have flagellum so they can swim to egg, have a lot of mitochondria, acrosome has digestive enzymes to break egg surface

Question 23

what are palisade mesophyll cells

Answer 23

contain chloroplasts, walls are thin for easy diffusion

Question 24

what are root hair cells

Answer 24

large surface area and thin permeable wall, extra mitochondria for active transport

Question 25

what are guard cells

Answer 25

pores in surface of leaf for gas exchange, in light they take up water and become turgid, they open stomata

Question 26

what is cartilage

Answer 26

type of connective tissue in joints, it shapes and supports ears, nose and windpipe

Question 27

what is xylem tissue

Answer 27

transports water around the plant and supports it, contain dead xylem vessel

Question 28

what is phloem

Answer 28

transports sugars, arranged in tubes and made up of sieve and companion cells