Biology Paper 2

Question 1

Homeostasis

Answer 1

An organisms ability to regulate/ control its internal conditions so crucial reactions (including those involving enzymes) can happen at optimal rates

Question 2

What makes up the nervous system

Answer 2

The central nervous system (brain and spinal cord) and the peripheral nervous system (all other nerves)

Question 3

Reaction time RP

Answer 3

Drop ruler between finger and thumb
Measure distance fallen before caught, repeat, calculate mean
Independent variable: Stimulant (energy drink) increases neurotransmission while Depressant (alcohol) decreases neurotransmission

Question 4

Endocrine system

Answer 4

System of glands that secrete hormones to send signals to effectors, transported via blood

Question 5

Thyroid gland

Answer 5

Controls growth, metabolism and more

Question 6

Pituitary gland

Answer 6

‘Master gland’: sends signals to other glands

Question 7

Adrenal glands

Answer 7

Release adrenaline

Question 8

Ovaries

Answer 8

Release eggs and secrete hormones

Question 9

Pancreas

Answer 9

Secretes insulin (and glucagon) to control blood sugar

Question 10

Testes

Answer 10

Produces sperm

Question 11

Type 1 diabetes

Answer 11

-Pancreas cannot produce enough insulin
-Injections needed

Question 12

Type 2 diabetes

Answer 12

-Cells do not absorb glucose as they should
-obesity increases risk of developing

Question 13

What happens if high blood glucose levels

Answer 13

-Pancreas secreates insulin
-Causes glucose to move from the bloodstream into cells to be used for respiration
-Excess glucose converted into glycogen as energy store

Question 14

What happens if Low blood glucose levels

Answer 14

-Pancreas secreates glucagon
-Causes liver and muslce cells to convert glycogen back into glucose (negative feedback)

Question 15

The menstrual cycle ad hormones

Answer 15

-FSH from pituitary gland causes an egg to mature, and the ovaries to produce…
-OESTROGEN causes uterus lining to thicken, and it inhibits fsh so no more eggs mature, it also causes the pituitary gland to secrete
-LH Causes egg to be released, which starts to travel towards uterus

-Progesterone secreted by ovaries maintains the uterus lining.

Question 16

Types of contraception

Answer 16

FSH-inhibiting pills, no eggs mature
Progesterone injection/implant to stop eggs being released
Condom/diaphragm: stops sperm entering vagina
IUD: stops egg embedding in lining
Avoiding sex for a time after egg released
Clamping oviduct or vasectomy (cutting sperm tubes)

Question 17

Fertility treatments

Answer 17

FSH/LH injections- Simple!

IVF- Hard/expensive, eggs collected after inducing release with LH to be fertilised in a lab and inserted back into uterus

Question 18

Meiosis

Answer 18

The process by which gametes are made- genetically different from parent cells.
1)Chromosomes copied
2)simillar chromosomes pair up and genes swapped between them
3)cell divides to produce two diploid cells
4)these divide again to produce 4 haploid cells

Question 19

Sexual reproduction

Answer 19

Requires 2 parents
Advantage- offspring become better adapted to enviroment

Question 20

Asexual reproduction

Answer 20

Happens by mitosis which means they will be identical
Advantage- Only one organism needed to reproduce

Question 21

Genome

Answer 21

The entire genetic code in an organism

Question 22

DNA

Answer 22

Double helix polymer- stores genetic code

Question 23

Gene

Answer 23

Portion of DNA that codes for a protien

Question 24

Genotype

Answer 24

An organisms specific genetic code

Question 25

Phenotype

Answer 25

How this code is expressed in physical characteristics

Question 26

Darwins theory of evolution

Answer 26

-Random mutations results in variation
-Some organisms better adapted to enviroment
-These compete (‘survivall of the fittest’)
-Those better adapted are more likely to survive; over time these desirable characteristics are more pronounced

Question 27

Lamarcks theory of evolution

Answer 27

-Mutations/adaptations are a result of enviroment affecting characteristics inherited by offspring: not random

Question 28

Antibiotic-resistant bacteria

Answer 28

Used as evidence for Darwinian evolution: if not all bacteria killed, those most resistant will reproduce. This is why you must complete the full course of antibiotics

Question 29

Selective breeding

Answer 29

Breeding organisms that have desired characteristics to produce offspring in which they are more pronounced

Question 30

Genetic engineering method

Answer 30

1)Desired gene is cut from another organisms DNA using enzyme
2)Gene inserted into a vector
3)Vector inserts gene into cells of another organism early in development
4)organism develops with desired characteristic

Question 31

Classification

Answer 31

KINGDOM
PHYLUM
CLASS
ORDER
FAMILY
GENUS
SPECIES

King Phillip Came Over For Good Soup

Binomial Name = GENUS + SPECIES

Question 32

Sampling RP

Answer 32

-Place quadrat in random positions in area using random number generator
-Count numgber of choson organism in each, calc mean then multiply by total area to get estimate for population

Question 33

Food chain

Answer 33

Producer
Primary comsumer
Secondary consumer
Tertiary consumer

Question 34

Water cycle

Answer 34

Water evarporates

Clouds cause rain

Rain runs into rivers