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Flashcards in April Test 3 Deck (47)
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1

What does evolution mean?

A gradual change in the characteristics of a species over time

2

Why is it hard to find evidence of evolution?

Because some is destroyed by earthquakes

3

How is the age of a stone tool worked out?

By looking at the rock it's made with

4

What is genetic variation?

The characteristics of individuals vary in a population due to gene difference

5

What is natural selection?

By chance some individuals have variations that make them better at coping and more likely to survive

6

What is inheritance?

Naturally selected survivors breed and pass on their variations to offspring

7

What's the best way to remember the classification of an animal?

Kings Play Chess On Fire Grain Sand

Kingdom
Phylum
Class
Order
Family
Genus
Species

8

What do plants have that animals don't?

Chloroplasts

9

Definition of species?

A group of similar organisms capable of reproducing

10

Definition of breed?

Members of an animal species differing from others slightly

11

Definition of variety?

Members of a plant species differing from others only slightly

12

What is artificial selection?

When humans breed organisms with useful characteristics to create new breeds/varieties with desired characteristics

13

Problems with selective breeding?

Takes a long time for desired characteristics

Large numbers may be disease prone

Concerns over animal welfare

14

What is a calorimetry?

The dry food flame experiment

15

What is diffusion?

Movement of particles from a high concentration to a low concentration

16

What is osmosis?

The net movement of water molecules across a partially permeable membrane from a high concentration to a low one

17

What is active transport?

The movement of particles across a membrane across a concentration gradient

18

Two differences between diffusion and active transport?

Active transport requires energy

In active transport particles are moved UP a concentration gradient not DOWN

19

What is a chromosome?

A coiled up length of DNA molecules

20

How do you calculate the number of cells produced by mitosis?

2^n

(n=number of divisions)

21

How is cancer caused?

When a cell starts dividing uncontrollably due to a change in one gene, causing a tumour

22

What is a stem cell?

An undifferentiated cell

23

Where are stem cells found?

In embryos

24

Risks of stem cells?

They divide very quickly

They may carry disease

The body may reject them

25

How does a reflex happen?

•Touch flame
•Receptor
•Sensory
•Synapse
•Relay
•Synapse
•Motor
•Effector

26

Why is alcohol added to DNA?

To get the DNA out as it isn't soluble in alcohol

27

What decides the order of amino acids in a protein?

The order of the bases

28

Instead of T what does mRNA use?

U

29

Transcription

•RNA polymerase binds to a region of DNA in front of a gene
•The two DNA strands unzip
•The RNA polymerase uses the coding DNA as a template to make mRNA
•The mRNA leaves the nucleus and joins with a ribosome

30

Translation

•tRNA brings amino acids to the ribosome
•Codon and anticodon make sure amino acids are in the right order
•Amino acids join together and a polypeptide is made