Biology Section 9 | Quizlet

How can farmers artificially increase plant growth?

- carbon dioxide by a paraffin heater

- light by using artificial light

- using a greenhouse to reflect the heat

- use greenhouse to reduce the amount of pests

Why do farmers use fertilizer?

to supply the plants with minerals they need to grow

What are the two ways to control pests, give an example?

- chemical: pesticides
- biological: predators

What is fermentation?

when micro organisms break down sugars to release energy

Describe how yogurt is made?

- all the equipment is sterilized to prevent any other microorganisms from interfering

- the milk is pasteurizes (heated high) then cooled

- the lactobacillus bacteria is added.

- the mixture is then heated constantly to 40 degrees for the bacteria

- the bacteria ferments the milk to lactic acid which causes the milk to thicken

- then flavors are added

What are fermenters?

they are a tool used to maximize the production of micro organisms

What tools in the fermenter are there to give 8?

- PH probe
- water jacket
- temperature probe
- stirring paddles
- air inlet
- nutrient inlet
- exhaust valve

What is the liquid the micro organisms growing in called?

culture medium

What is the function of the probes?

to monitor the conditions inside to make sure they are optimal

What are the nutrient inlets for?

they provide nuitrients for the micro organisms to grow

What is the exhaust and air inlet for?

provide air for the micro organisms to respire and removes the products of respiration

What is the function of the water jacket?

maintains the temperature does not become too high

What is the function of the paddles?

they mix the culture medium so that the micro organisms can come in contact with nutrientsnts

Why is the equipment sterilized in fermenters?

to avoid any unwanted micro organisms competing with resorces

When all the equipment has been sterilised what type of condition is the environment?

aseptic

How is bread made?

- you mix yeast, bread, water, and sugar

- the dough is left in a war m place for the enzymes in the yeast to work best

- the yeast enzymes break down the sugar for respiration which produces carbon dioxide bubbles

- when the oxygen is gone the yeast switches to anaerobic respiration and makes ethanol and more carbon dioxide

- the dough is then baked and the ethanol evaporates

- the yeast dies and the bread stops rising

Describe the experiment that tests yeasts rate of respiration?

- make a solution of yeast, sugar and distilled water (no oxygen)

- add a layer of oil over this solution to prevent an oxygen

- place this in water bath of a temperature and see how long it takes for the limewater to turn cloudy

- the yeast makes carbon dioxide because it respires anaerobically by breaking down the sugar

How does selective breeding work?

- you breed two organisms with the desired characteristics

- then out of the offsprings you select the best and breed them together

- this process keeps occurring until all of the offspring's have the characteristic

What is artificial insementaion?

to speed up the breeding process the sperm of one organism is injected straight to the uterus of the other

What is a advantage to selective breeding?

- its faster than naturally

What is a disadvantage to selective breeding?

- if you keep breeding offspring's the variation will decrease, if they are not immune to a virus it will kill all of them

- the gene pool shortens