biology

Question 1

what is the endocrine system made up of

Answer 1

endocrine glands

Question 2

what do the endocrine glands secrete

Answer 2

hormones into the blood

Question 3

what does the endocrine system regulate

Answer 3

maintenance of internal homeostasis, growth and development, use of energy, salt and sugar levels in the blood, amount of fluids, stress, appetite

Question 4

what is the master gland and why

Answer 4

the pituitary gland controls the functions of many of the other endocrine glands

Question 5

example of an endocrine disorder and cause

Answer 5

diabetes, pancreas doesn’t produce enough insulin/insulin isn’t used properly by the body

Question 6

what are target cells

Answer 6

cells with a matching shaped receptor to the signalling hormone

Question 7

what is a hormone

Answer 7

a signalling molecule

Question 8

what do hormones do

Answer 8

send signals internally, long acting and slower to be received

Question 9

what do nerve signals do

Answer 9

send signals internally, short acting but send a message quickly

Question 10

how does a hormone travel

Answer 10

through the bloodstream

Question 11

what controls the release of hormones

Answer 11

external and internal stimuli

Question 12

how is external stimuli received

Answer 12

through the nerves from the sensory organs in the nervous system

Question 13

examples of external stimuli

Answer 13

temperature change, hearing a loud noise, something scary

Question 14

how is internal stimuli received

Answer 14

through the nerves and other hormones in the body

Question 15

examples of internal stimuli

Answer 15

hunger, thirst, being sick

Question 16

what is homeostasis

Answer 16

the bodies ability to maintain a constant internal environment, despite changes to the external environment

Question 17

what conditions need to be constant

Answer 17

temperature and blood glucose level

Question 18

how is homeostasis maintained

Answer 18

through a negative feedback loop

Question 19

what does SRBERN stand for

Answer 19

stimulus, receptor, brain, effector, response, negative feedback

Question 20

what happens in the stimulus stage

Answer 20

the change that triggers the negative feedback

Question 21

what happens in the receptor stage

Answer 21

signal is received/detected (chemo or thermo receptors

Question 22

what happens in the brain stage

Answer 22

receives message and sends message to effectors

Question 23

what happens in the effector stage

Answer 23

the responding organ receives the message and respond

Question 24

what happens in the response stage

Answer 24

the organ responds and the stimulus reverses

Question 25

what happens in the negative feedback stage

Answer 25

original stimulus is reversed and brain tells effectors to stop

Question 26

what is a positive feedback loop

Answer 26

brain tells effectors to keep going, response keeps occurring e.g giving birth, hormones keep coming

Question 27

what are chromosomes

Answer 27

structures made of a tightly wound DNA, found in nucleus

Question 28

what are genes

Answer 28

segments of DNA that code for a specific protein which determines traits

Question 29

what is a genome

Answer 29

complete instructions for making an organism

Question 30

what is the function of DNA

Answer 30

contains instructions for making proteins which code for traits

Question 31

what is the structure of DNA

Answer 31

double helix shape, made of nucleotides and held together by hydrogen bonds

Question 32

what makes up a nucleotide

Answer 32

phosphate, deoxyribose sugar and a nitrogenous base (A, T, C, G)

Question 33

what is the base pairing rule

Answer 33

adenine with thymine and cytosine with guanine

Question 34

what is the main function of RNA

Answer 34

create proteins by translation

Question 35

structure of RNA

Answer 35

phosphate, ribose sugar and nitrogenous base (A, U(uracil), G, C)

Question 36

similarities between DNA and RNA

Answer 36

both have nucleotides with same structure, follow same phosphate sugar backbone, G and C pairing is the same

Question 37

differences between DNA and RNA

Answer 37

RNA is single stranded, sugar is different, RNA can leave the nucleus

Question 38

what are proteins and what are they made of

Answer 38

made up of amino acids and code for particular traits

Question 39

how is a protein produced (from DNA)

Answer 39

transcription - DNA is copied into a RNA molecule by polymerase enzyme, translation - RNA travels to a ribosome and decodes RNA into amino acids that form proteins

Question 40

what are the stages of the cell cycle

Answer 40

G1, S, G2, mitosis (PMAT) and cytokinesis

Question 41

what occurs in the G1 phase

Answer 41

The cell grows in mass and size by creating more proteins

Question 42

what occurs in the S phase

Answer 42

DNA is replicated (synthesised), chromosomes are doubled

Question 43

what occurs in the G2 phase

Answer 43

the cell continues to grow by making more organelles

Question 44

what occurs in the mitotic phase

Answer 44

in 4 stages, the cell divides chromosomes evenly and gets the cell ready to split into 2

Question 45

what occurs in the cytokinesis phase

Answer 45

the cytoplasm is divided and creates 2 new cells, in animal cells the cell membrane pinches (cleavage furrow) and in plant cells a cell plate is produced dividing the 2 daughter cells and then thickens into a cell wall

Question 46

what percent/time of the cell cycle is mitosis

Answer 46

10%, 1 to 2 hours

Question 47

what are the 4 stages of mitosis

Answer 47

prophase, metaphase, anaphase and telophase

Question 48

when does mitosis occur

Answer 48

after G2 (interphase)

Question 49

what occurs in prophase

Answer 49

DNA coils and chromosomes become visible, nucleus disappears and centrioles begin forming the spindle fibres

Question 50

what occurs in metaphase

Answer 50

chromosomes attach to the spindle by the centromere and line up in the middle of the cell (equator)

Question 51

what occurs in anaphase

Answer 51

centromere splits and sister chromatids seperate and are pulled to opposite ends of the cell by spindle fibres

Question 52

what occurs in telophase

Answer 52

chromosomes begin to uncoil, spindle fibres disappear and nuclear membrane re-forms

Question 53

what do cell checkpoints do

Answer 53

check the cell (DNA) for any damage, ensures it has enough nutrients and ensures the DNA has been properly replicated

Question 54

what do mutations cause

Answer 54

uncontrollable cell division and may lead to cancer

Question 55

when is DNA replicated and why

Answer 55

in the S phase to ensure new daughter cells will have the same, matching DNA to the parent cell

Question 56

what does the helicase do in DNA replication

Answer 56

it unzips and unwinds DNA

Question 57

what does the DNA polymerase do in DNA replication

Answer 57

creates a new DNA strand by joining nucleotides, turns one strand of DNA into 2

Question 58

what is produced at the end of DNA replication

Answer 58

2 new daughter strands (with 2 parent strands)

Question 59

why do cells need to divide/reproduce

Answer 59

to grow the organism and repair and replace the damaged cells

Question 60

what are the cells called after division

Answer 60

daughter cells

Question 61

what does not enough mitosis cause

Answer 61

it doesn't allow for cells to grow or repair/replace damaged cells

Question 62

what does too much mitosis cause

Answer 62

can lead to cancer due to uncontrolled cell division, cells may mutate in uncontrolled division