100% satisfaction guarantee Immediately available after payment Both online and in PDF No strings attached
logo-home
Summary AQA level 3 extended certificate - Applied science - Unit 4 - Human Biology revision notes $5.86   Add to cart

Summary

Summary AQA level 3 extended certificate - Applied science - Unit 4 - Human Biology revision notes

1 review
 106 views  3 purchases
  • Course
  • Institution
  • Book

This document gives summary notes for unit 4 Human Biology. Let me know if you have any questions.

Preview 2 out of 14  pages

  • Yes
  • June 27, 2023
  • 14
  • 2022/2023
  • Summary

1  review

review-writer-avatar

By: jasminelouis • 1 year ago

avatar-seller
Applied science – The human body

Digestive system




Figure 1 - human digestive system



Mouth- where the food enters the digestive system, contains salivary glands
Salivary glands- produces amylase and saliva which break down starch.
Oesophagus- tube which transports food from mouth to stomach, it causes peristalsis
allowing food to move down into stomach.
Liver- produces bile which neutralizes stomach pH and emulsifies fats.
Gall bladder- where bile is stored and then released.
Stomach- protease enzyme pepsin is produced here, as well as HCl which maintains the
stomachs acidic conditions as well as killing bacteria.
Pancreas- produces amylase, protease, and lipase, which are then released into the
small intestine
Small intestine- produces protease, amylase, and lipase to complete the digestion
process.
Large intestine- where excess water and nutrients are absorbed from foods.

, Figure 2 – Descriptive table about Amylase, Maltose, Endopeptidase, Exopeptidase, Dipeptidase and Lipase enzymes

Types of digestion

Mechanical- physical breakup of food molecules into smaller molecules, allowing
enzymes to act.
Chemical- breakdown of complex molecules into simple molecules.

Hydrolysis and condensation reactions

Hydrolysis- insertion of water molecule which breaks bonds e.g. peptide, glycosidic
Condensation- elimination of water molecules, causing joining of components.

Absorption in the small intestine

Adaptations to max absorption

1. Good blood supply which maintains the concentration gradient.
2. Epithelium is one cell thick so there is a short diffusion pathway.
3. Epithelium cells have microvilli on their surface, which allows a greater surface area.
4. Lacteals run into each villus, these absorb glycerol and fatty acids.

Absorption of glucose and protein in ileum

Glucose and protein are absorbed in the ileum by co-transportation.
1. Na+ ions are actively transported out of epithelial cell into blood, which lowers
Na+ concentration in the epithelial cell.
2. Na+ enters a cell from gut down concentration gradient via a carrier, this
generates energy which allows the same carrier to actively transport glucose into
cell.
3. Low concentration of glucose in cell rises, therefore glucose can move into blood
down concentration gradient via facilitated diffusion.
4. Na+ also moves into blood, but it is not co-transported with glucose in this way.

Amino acids are also absorbed in the same way as glucose but use different carriers.

The benefits of buying summaries with Stuvia:

Guaranteed quality through customer reviews

Guaranteed quality through customer reviews

Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.

Quick and easy check-out

Quick and easy check-out

You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.

Focus on what matters

Focus on what matters

Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!

Frequently asked questions

What do I get when I buy this document?

You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.

Satisfaction guarantee: how does it work?

Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.

Who am I buying these notes from?

Stuvia is a marketplace, so you are not buying this document from us, but from seller nathanbates. Stuvia facilitates payment to the seller.

Will I be stuck with a subscription?

No, you only buy these notes for $5.86. You're not tied to anything after your purchase.

Can Stuvia be trusted?

4.6 stars on Google & Trustpilot (+1000 reviews)

75759 documents were sold in the last 30 days

Founded in 2010, the go-to place to buy study notes for 14 years now

Start selling
$5.86  3x  sold
  • (1)
  Add to cart