Unit 3 - The Cell (part 1)

Question 1

4 types of receptors

Answer 1

• G-coupled receptor - releases a subunit which makes enzymes active
• receptor tyrosine kinases - membrane receptors that attach phosphates to tyrosine kinases
• Ion channel receptors
• intracellular receptors

Question 2

cellular messaging -local -long distance

Answer 2

-direct contact, cell-cell recognition, gap junctions (plasmdesmata in plants), local regulators (send messages short distance) ex. growth factors tell cells to divide -HORMONES : sent through blood and picked up by specific target

Question 3

cell division regulation -G1 checkpoint -G0 -G2 checkpoint -m checkpoint

Answer 3

-checks to see if there are enough nutrients and if the cell is big enough to grow -after lack of nutrients or growth factors, G1 checkpoint is not passed and cell enters G0. stays here until detects reason to divide -evaluates if DNA replication is finished -checks that chromosomes are properly arranged

Question 4

epinephrine

Answer 4

chemical released that determines fight or flight

Question 5

starving cells and their actions

Answer 5

-secrete a chemical that tells neighboring cells to aggregate -form a “fruiting body” -which can survive until more nutrients arive

Question 6

MPF

Answer 6

mitosis promoting factor (cyclin dependent kinase) -phosphorlyzes other kinases which causes -fragmentation of nuclear envelope -destruction of cyclin

Question 7

kinase

Answer 7

always present, transfers phosphates from ATP to protein -can activate phosphorolase kinase which hydrolyses glycogen

Question 8

centrosome

Answer 8

where spindle fibers assembly begins - centrioles @ center

Question 9

kinetochore

Answer 9

region of centromere where microtubuoles attach

Question 10

mitotic spindle

Answer 10

fibers of microtubules & proteins comes from cytoskeleton made of TUBULIN - protein

Question 11

cleavage furrow

Answer 11

indentation of cell spliting

Question 12

cell plate

Answer 12

harder for plant cells to pinch closed because of cell wall so cell plate forms to divide cell wall

Question 13

nucleosome

Answer 13

a bundle of DNA and histone

Question 14

cell division

• genome
• chromatin

Answer 14

asexual reproduction - the 2 cellls are clones of eachother

• cells genetic info, DNA
• DNA and protein in nucleus