Oxygen
Sugar
Bacteria
Carbon dioxide
Yeast in Food Production
- Microorganisms can be used by humans to produce foods and other useful substances.
- One example of this is the production of bread using yeast.
- Yeast is a single-celled fungus that can carry out both aerobic and anaerobic respiration.
Making bread : During bread making yeast is added to bread dough. The yeast produces enzymes that break down the starch in flour, releasing sugars that can be used by the yeast in respiration. The yeast begin to respire aerobically but will switch to anaerobic respiration when oxygen runs out. When yeast carries out anaerobic respiration it produces alcohol (ethanol) and carbon dioxide. The carbon dioxide produced by the yeast is trapped in small air-pockets in the dough, causing the dough to rise (increase in volume). The dough is then baked in a hot oven to form bread. During baking any ethanol produced by the yeast is evaporated in the heat, so bread doesn’t contain any alcohol. The yeast is killed by the high temperatures used during baking. This ensures there is no further respiration by the yeast.
If you are interested in preparing for the CSS MPT and other FPSC, SPSC, and PPSC General Recruitment Tests with us, get in touch with us.
Related MCQs
- How many times the word “Mubeen” is Repeated in Surah Yasin? (CSS 2022 Islamic Studies Paper)
- Five times
- Six times
- Six times
- Seven times
Submitted by: None of these
- Soil pollution is caused by? (CSS 2023 Special General Science & Ability Paper)
- Ozone
- Aerosol
- Acid rain
- All of these
Submitted by: CSS Exam Desk Team
- One Units system was abolished in? (CSS 2019 Pakistan Affairs Paper)
- 1948
- 1970
- 1971
- None of these
Submitted by: CSS Exam Desk Team
- “Truth is sought for its own sake. And those who are engaged upon the quest for anything for its own sake are not interested in other things. Finding the truth is difficult, and the road to it is rough.” This was stated by which key figure in the development of scientific method in the 11th century?
- Plato
- Aristotle
- Ibn al-Haytham
- None of these
Submitted by: CSS Exam Desk Team
- Masjid Qiblatain is situated in? (CSS 2013 Islamic Studies Paper)
- Madinah
- Makkah
- Taif
- Jabal e Noor
Submitted by: CSS Exam Desk Team
- Change the voice of the following sentence: Rain disrupted the last day’s play between Pakistan and Australia. (CCE 2023 Screening Test, December 1, 2024)
- The last day’s play of Pakistan and Australia was disrupted by rain.
- Pakistan and Australia’s play of the last day as disrupted by rain.
- The last day’s play between Pakistan and Australia was disrupted by rain.
- The last day’s play between Pakistan and Australia were disrupted by rain.
Submitted by: CSS Exam Desk Team
- Who was the second Governor-General of Pakistan? (CSS 2019 Pakistan Affairs Paper)
- Khawaja Nazimuddin
- Ghulam Muhammad
- Iskandar Mirza
- None of these
Submitted by: CSS Exam Desk Team
- The SYNONYM of the word \"CAJUN\" is? (CSS 2006 English Precis & Composition Paper)
- American Indian
- Native of the Everglades
- French-Canadian descendant
- Early inhabitant of the Bahamas Islands
Submitted by: CSS Exam Desk Team
- AshabusSabt mean? (رضی اللّٰہ عنہ)
- Jews
- Christians
- Muslims
- Sabieen
Submitted by: CSS Exam Desk Team
- Photography works by? (CSS 2012 General Science & Ability Paper)
- Capturing light reflected from the object being photographed
- Capturing the souls of the objects being photographed
- Both of these given options
- None of these given options
Submitted by: CSS Exam Desk Team
- The most significant greenhouse gas is? (CSS 2013 Current Affairs Paper)
- Ozone
- Chlorofluorocarbons
- Carbon Dioxide
- None of these
Submitted by: CSS Exam Desk Team
- Incident of Miraj is present in Quran, How many times? (CSS 2014 Islamic Studies Paper)
- One
- Twice (Israa, 1st surat of 15th para and in Surat An Najam)
- Three
- None of these
Submitted by: CSS Exam Desk Team
- Hajj Scam 2010 struck a blow to? (CSS 2011 Current Affairs Paper)
- Fazal-ur-Rehman
- Azam Swati, Hamid Saeed Kazmi
- Ishaq Dar
- Inamullah
Submitted by: CSS Exam Desk Team
- Jabal-e-Noor is situated in? (CSS 2013 Islamic Studies Paper)
- Arafat
- Ghar-i-Hira
- Ghar-i-Saur
- None of these
Submitted by: CSS Exam Desk Team
- The recently published book \" Between Dreams and Realities\" is written by? (CSS 2010 Current Affairs Paper)
- Shamshad Ahmad Khan
- Gohar Ayub
- Sahibzada Yakoob Ali Khan
- None of these
Submitted by: CSS Exam Desk Team
- The author of the book “Reconciliation: Islam, Democracy, and the West”? (CSS 2023 Current Affairs Paper)
- Ahmad Rashid
- Stanley Wolpert
- Benazir Bhutto
- None of these
Submitted by: CSS Exam Desk Team
- Which rocks are formed by the alteration of pre-existing rocks by great heat or pressure? (CSS 2011 General Science & Ability Paper)
- Igneous rocks
- Sedimentary rocks
- Metamorphic rocks
- Acid rocks
Submitted by: CSS Exam Desk Team
- Longest Surah of Quran? (CSS 2016 Islamic Studies Paper)
- Al-Baqarah (the Cow)
- At-Taubah (the Repentance)
- Al-Mu’minun (the Believers)
- Al-Fat’h (the Victory)
Submitted by: CSS Exam Desk Team
- The discipline which deals with the understanding and treatment of mental health is called? (CSS 2014 General Science & Ability Paper)
- Applied psychology
- Clinical psychology
- Psychoanalysis
- Psychiatry
Submitted by: CSS Exam Desk Team
- the incident of meeraj has been discussed in surah? (CSS 2012 Islamic Studies Paper)
- Al-baqarah
- Bani Israel
- Al-tauba
- yunus
Submitted by: CSS Exam Desk Team
- Pamphlet ‘Now or Never’ was written by? (CSS 2019 Pakistan Affairs Paper)
- Ch Rahmat Ali
- Quaid-e-Azam
- Sir Syed
- None of these
Submitted by: CSS Exam Desk Team
- “ Falyabudu “ means? (CSS 2015 Islamic Studies Paper)
- He made them incline
- Who gave them food in hunger
- They should worship
- None of these
Submitted by: CSS Exam Desk Team
- The total length of the Pakistan Coastal line is? (CSS 2023 Pakistan Affairs Paper)
- 1315km
- 1200km
- 1000km
- 1046km
Submitted by: CSS Exam Desk Team
- What is Anthracite? (CSS 2019 General Science & Ability Paper)
- Carbon
- Pure Carbon
- Ammonia
- None of these
Submitted by: CSS Exam Desk Team
- 2020 PSL Champions are? (CSS 2021 Current Affairs Paper)
- Karachi Kings
- Lahore Qalanders
- Islamabad United
- None of these
Submitted by: CSS Exam Desk Team