Module 2- Cell division, diversity and organisation

Question 1

What are the 2 major phases of the cell cycle?

Answer 1

-interphase
-mitotic phase

Question 2

What happens during interphase (3 stages)?

Answer 2

G1=the cell grows
S=DNA synthesis happens
G2=the cell grows more

Question 3

What happens during mitotic phase?

Answer 3

-eukaryotic cell divides to produce 2 genetically identical daughter cells

Question 4

Why do multicellular organisms go through mitosis?

Answer 4

-multi cellular organisms go through mitosis to grow and repair damaged tissue

Question 5

What happens at the first checkpoint G1?

Answer 5

-DNA is checked to ensure there’s no damage, the cell is the right size and has enough energy reserves

Question 6

What happens at the second checkpoint G2?

Answer 6

chromosomes are checked to ensure they have all been replicated and none of the DNA is faulty

Question 7

What happens at the 3rd checkpoint M?

Answer 7

sister chromatids are checked to confirm that their attachment to the spindle are suitable

Question 8

What happens during interphase of mitosis?

Answer 8

-cell prepares to divide
-DNA is replicated via semi conservative replication
-organelles are replicated
-more ATP is produced to use during cell division

Question 9

What happens during prophase of mitosis?

Answer 9

-nuclear envelope and nucleolus break down
-chromosomes are left floating in the cytoplasm
-chromosomes coil more tightly and become shorter and flatter
-centrioles move to opposite poles of the cell
-microtubules form mitotic spindle between the centrioles

Question 10

What happens during metaphase of mitosis?

Answer 10

-chromosomes line up along the mid line of the cell
-chromsomes are the most condensed
-chromosomes are attached to the spindle by the centromere

Question 11

What happens during anaphase of mitosis?

Answer 11

-chromosomes break down into chromatids
-the 2 sister chromatids separate at the centromere
-the spindles contract and pull the chromatids to each end of the cell

Question 12

What happens during telophase of mitosis?

Answer 12

-chromatids reach the opposite poles and begin to decondense becoming chromosomes again
-nuclear envelope reforms to form 2 nuclei
-the cytoplasm splits and 2 daughter cells are formed

Question 13

What is the significance of mitosis?

Answer 13

-asexual reproduction
-allows single celled organisms to reproduce rapidly
-allows somatic cells to reproduce and form clones that can perform the exact same function within the body as parent cells
-introduces no genetic variation

Question 14

What does meiosis produce?

Answer 14

production of haploid gametes from diploid cells

Question 15

What happens in interphase in meiosis?

Answer 15

chromosomes replicate

Question 16

What happens in prophase 1 of meiosis?

Answer 16

chromosomes condense to form a double armed chromosome
-each arm is made from 1 chromatid and is joined by a centromere

Question 17

What happens in metaphase 1 of meiosis?

Answer 17

chromosomes in a homologous pair are arranged in the centre of the cell

Question 18

What happens in anaphase 1 of meiosis?

Answer 18

homologous chromosomes are separated and pulled to opposite ends of the cell by spindle fibres

Question 19

What happens in telophase 1 of meiosis?

Answer 19

random combinations of chromosomes are pulled to each side of the cell

Question 20

What happens in cytokinesis 1 of meiosis?

Answer 20

the cell divides into 2 cells which are genetically different

Question 21

What happens in prophase 2 of meiosis?

Answer 21

chromatids condense again

Question 22

What happens in metaphase 2 of meiosis?

Answer 22

chromosomes line up in the centre of the cell

Question 23

What happens in anaphase 2 of meiosis?

Answer 23

sister chromatids are separated from spindle fibres and pulled to opposite ends of the cell

Question 24

What happens in telophase 2 of meiosis?

Answer 24

as the sister chromatids are separated the cell divides into 2 cells

Question 25

What happens in cytokinesis 2 of meiosis?

Answer 25

4 genetically different cells are produced

Question 26

What is the significance of meiosis?

Answer 26

-sexual reproduction -individual inherits one copy of a chromosome from each parent -produces gametes -any 2 gametes could fuse together to produce any combination of chromosomes

Question 27

How is genetic variation generated in each daughter cell?

Answer 27

-crossing over-sections of DNA are swapped between the chromosomes in a pair producing new combinations of alleles -independent assortment-chromosomes in a homologous pair are separated in meiosis 1 in a random formation

Question 28

What are neutrophils and their adaptations?

Answer 28

-phagocytotic leukocytes involved in one of the early lines of defence against pathogens -multilobed nucleus so cell can squeeze through small gaps to get to the site of infection -lots of lysosomes to digest enzymes

Question 29

What are guard cells and their adaptations?

Answer 29

-control the opening and closing of the stomata -when guard cells are flacid the stomata close -when guard cells are turgid the stomata open -large vacuole for water to move in and out via osmosis

Question 30

What are root hair cells and their adaptations?

Answer 30

-lots of mitochondria for a.t -lots of mineral ions in cytoplasm lowers the w.p so water moves into the roots via osmosis -hair like projection increases surface area for osmosis -don't contain chloroplast as they are underground so can't photosynthesise

Question 31

What are sperm cells and their adaptations?

Answer 31

-acrosome in the head of the sperm contains digestive enzymes to enter the egg -streamlined shape for faster movement -lots of mitochondria to provide more energy as travel far

Question 32

What are squamos epithelial cells and their adaptations?

Answer 32

-small and flat -sensory nerve endings are embedded within to allow outside sensory stimuli to be received -allows for selective transport of substances

Question 33

What are red blood cells and their adaptations?

Answer 33

-biconcave shape to increase surface area to absorb more oxygen via diffusion -no nucleus so there is more space to carry oxygen -small and flexible to squeeze through small capillaries

Question 34

Name all the components of the digestive system

Answer 34

pancreas, stomach, liver, small intestine, large intestine, salivary glands

Question 35

Name the 4 types of stem cells

Answer 35

totipotent, pluripotent, multipotent, unipotent

Question 36

What are totipotent cells?

Answer 36

-exist for only a very limited time during embryonic development in mammals -during development they translate only part of their DNA meaning the cells remain unspecialised -are able to produce any type of blood cell as well as cells of supportive structures

Question 37

What are pluripotent cells?

Answer 37

-are able to divide unlimited numbers and produce any type of cell that makes up the body -can be used to treat human disorder

Question 38

What are multipotent cells?

Answer 38

-found in mature mammals -can develop into a limited number of cell types

Question 39

What are unipotent cells?

Answer 39

-found in mature mammals -can divide to produce new cells but can only produce 1 type of cell

Question 40

Where can stem cells be taken from?

Answer 40

-adult stem cells, embryonic stem cells, induced pluripotent stem cells

Question 41

What can stem cells be used for?

Answer 41

-reduce preventable deaths -treat conditions that decrease QOL

Question 42

What are induced pluripotent cells used for and how are they made?

Answer 42

-to treat disease -help avoid ethical issues of using embryos -somatic cells are converted into IP cells by activating genes using appropriate protein transcription factors -this makes somatic cells unspecialised

Question 43

What is a benefit of induced pluripotent cells?

Answer 43

-can be made from patients own body cells, decreasing the chance of rejection during transplants

Question 44

What stem cells do bone marrow transplants use?

Answer 44

multipotent stem cells

Question 45

What are bone marrow transplants used for?

Answer 45

treat blood and immune disorders

Question 46

What are the developmental applications of stem cells?

Answer 46

-used to develop artificial tissues -used to see how an embryo develops and organs are formed