Science ocr

acceleration=change in speed/time taken

On a speed-time graph:

Section under the line = distance travelled

Horizontal line=constant speed

Ion is a charged atom: Positive ion-loses an electron Negative ion-gains an electron

Ionic bonding:

-metal atoms transfer electrons to become positive ions

-non-metal atoms gain electrons to become negative ions

-Positive and negative ions are attracted to each other.

They have...

-high melting points

-conduct electricity when molten or in solution

-can't conduct electricity when solid as ions are held in place and cant move

1.If a root grows towards gravity, the response is called:

2. Why does the shoot bend towards the light when light shines on it from one side?

3. Plant hormones control when the 'eyes' of a potato start to sprout. This is an example of: 4Auxin is a plant hormone because: 5. Compared to plants grown in normal conditions, plants grown with light only from one side______________________

1.positive geotropism

2.Hormones in direct sunlight are destroyed, hormones on shaded side continue to function, causing cells to elongate

3.Dormancy

4.Auxin is a plant hormone because it controls different parts of the plant.

5.Will have longer stems

Natural selection

• Individuals in a species show a wide range of variation.
• This variation is because of differences in genes.
• Individuals with characteristics most suited to the environment are more likely to survive and reproduce.
• The genes that allowed the individuals to be successful are passed to the offspring in the next generation.

Lamark's theory: Evolution happened by the inheritance of acquired characteristics

1. Organisms change during the lifetime

2.Changes are passed on to their offspring

Fossil records are incomplete because some body parts may not have been fossilised, fossilitation occurs rarely.

1.Fill in the gaps: The base sequence of _____________ is altered by mutations. This changes or prevents the production of the ____________ for which the gene normally codes.

2.Production of insulin: The human gene for insulin production is _________________. The gene is ____________ and removed using an enzyme. A ring of _______________ DNA is cut open using an enzyme. The section of human DNA is inserted into the ______________. tHE ________is reinserted into the bacterium where it ____________ rapidly. The bacteria are _____________on a large scale to make insulin.

3. Which of these is NOT a problem caused by selective breeding?

May damage wildlife in surrounding areas, more likely to suffer genetic disease, Less genetic variation in future populations

1.-DNA

-PROTEIN

2.-SELECTED, ISOLATED, BACTERIA, PLASMID, PLASMID, DIVIDES, CULTIVATED

3.May damage wildlife in surrounding areas