body balance

Question 1

what is homeostasis

Answer 1

The body’s ability to maintain a constant internal environment, even when there are changes in the external environment.

Question 2

What are some of the conditions in the body that need to be kept constant?

Answer 2

body temperature at 37°C
the amount of water inside our body
blood sugar levels

Question 3

How does the body maintain homeostasis?

Answer 3

the negative feedback loop

Question 4

Describe an example of negative feedback

Answer 4

When it gets cold outside (stimulus) you shiver (response) and keep the temperature inside your body from dropping.

Question 5

the stimulus response model order

Answer 5

stimulus, receptor, control centre, effector, responce

Question 6

What is a Negative-Feedback Loop?

Answer 6

Aims to reverse the effects of a stimulus

Question 7

What is a Positive-Feedback Loop?

Answer 7

Aim to increase the effects of a stimulus

Question 8

what is the role of the endocrine system

Answer 8

to release hormones (chemical messengers), from endocrine glands, into the bloodstream.

Question 9

hypothalamus

Answer 9

detects change and signals the pituitary gland

Question 10

what does the endocrine system regulate

Answer 10

things like growth, water balance, reproduction and metabolism.

Question 11

what are the endocrine glands

Answer 11

Adrenal gland, pituitary Gland, pancreas, Thyroid Gland, Ovaries, Testes

Question 12

Adrenal gland

Answer 12

Hormones Released: Adrenaline and Cortisol
Function: Stress response, blood pressure, emergency response

Question 13

Pituitary Gland “Master Gland”

Answer 13

Hormone Released: Releases many including Growth Hormone
Function: Works closely with Hypothalamus

Question 14

Pancreas

Answer 14

Hormone Released: Insulin and Glucagon
Function: controls blood glucose levels.

Question 15

Thyroid gland

Answer 15

Hormone released: Thyroxine
Function: Metabolism & body heat

Question 16

Ovaries

Answer 16

Hormone released: Estrogen and Progesterone
Function: Menstruation and pregnancy

Question 17

Testes

Answer 17

Hormone released: Testosterone
Function: Production of sperm

Question 18

How do these hormones identify their target cells?

Answer 18

Cell surface receptors. Example: Glucagon is released by the pancreas when blood sugar levels drop. The glucagon recognise the receptors on the liver cells, instructing them to cause an increase in blood glucose.

Question 19

Example of endocrine disorder

Answer 19

diabetes

Question 20

DNA

Answer 20

contains the genes which code for a specific protein

Question 21

What are Chromosomes

Answer 21

tightly coiled, organised pieces of DNA

Question 22

What are genes

Answer 22

Genes are segments of DNA, they are made of nucleotide sequences.

Question 23

What do genes code for?

Answer 23

proteins

Question 24

What is the difference between a gene and a genome.

Answer 24

A gene is a specific segment of DNA, and a genome is the entirety of the genetic material inside an organism.

Question 25

What is DNA made up of

Answer 25

made up of repeating monomers, called nucleotides

Question 26

What is RNA

Answer 26

Is single-stranded and does not have to stay in the nucleus.

Question 27

What is the structure of RNA?

Answer 27

RNA contains nucleotides, with ribose sugar instead of deoxyribose sugar in dna. the base pairs are A and U, C and G

Question 28

What is the purpose of RNA

Answer 28

To read the DNA code, copy it and take the information out of the nucleus.To make proteins at the ribosomes !

Question 29

DNA → RNA → Protein

Answer 29

transcription and translation

Question 30

Transcription

Answer 30

it is in the nucleus, DNA → RNA

Question 31

Translation

Answer 31

It is in the ribosome, RNA → protein(chain of amino acids)

Question 32

RNA vs DNA

Answer 32

RNA: can leave the nucleus, Contains Uracil, Single stranded, Ribose sugar DNA: Can NOT leave the nucleus, Contains Thymine, Double stranded, Deoxyribose sugar

Question 33

What are the three main phases of the cell cycle

Answer 33

Interphase, mitosis, cytokinesis

Question 34

Interphase

Answer 34

Longest period of cycle, Normal cell functions (existing), - G1 - S - replication of DNA - G2

Question 35

Mitosis

Answer 35

PMAT -cell divides nuclear content -prophase, metaphase, anaphase, telophase

Question 36

Cytokenesis

Answer 36

Final split and formation of new, identical cells

Question 37

G1

Answer 37

Growth of cell before the DNA is replicated

Question 38

S

Answer 38

DNA replicated using DNA polymerase (enzyme)

Question 39

G2

Answer 39

Final growth period before cell divides into two, through Mitosis

Question 40

DNA replication is semi-conservative

Answer 40

Each new DNA molecule contains one of the original strands.

Question 41

Mitosis (cell division)

Answer 41

Now that the cell contents have doubled, it is time for the cell to divide into two identical, daughter cells

Question 42

Stages of mitosis

Answer 42

Prophase, metaphase, anaphase and telophase

Question 43

Prophase

Answer 43

Chromosomes become visible Nucleus membrane disappears Centrioles begin to move to poles

Question 44

Metaphase

Answer 44

Chromosomes line up at equator Spindle fibres are attached to centromeres

Question 45

Anaphase

Answer 45

Spindle fibres pull sister chromatids apart

Question 46

Telophase

Answer 46

Chromosomes are separated Nuclear membrane reforms Cell plate or cleavage furrow forms

Question 47

Cytokinesis (final stage)

Answer 47

The final split. in plants: Cell plate forms and will become the new cell wall In animals: Cleavage furrow forms, pinching the cells apart

Question 48

What is produced at the end of the process of DNA replication?

Answer 48

two identical new DNA molecules.