Question

please help me anwser these questions

1. Phosphoglycerides – what are they comprised of chemically? how do you recognize them?

2. what are sphingolipids and where they are found in animal cells?

3. explain secondary active transport

4. what are the light-dependent and light-independent phases of photosynthesis?

Answer 1

1. Phospholglycerides are esters of only two fatty acids, phosphoric acid and a trifunctional alcohol - glycerol (IUPAC name is 1,2,3-propantriol). The fatty acids are attached to the glycerol at the 1 and 2 positions on glycerol through ester bonds.

2. Complex sphingolipids located in the plasma membrane of animal cells (especially nerve cells) have a structural function and are believed to protect the cell surface from harmful environmental factors.

3. Secondary active transport: Secondary active transport or co-transport, also uses energy to transport molecules across a membrane; however, in contrast to primary active transport, there is no direct coupling of ATP; instead, the electrochemical potential difference created by pumping ions out of the cell is instrumental.

Light-dependent and light-independent reactions are two successive reactions that occur during photosynthesis.

Key Points

In light-dependent reactions, the energy from sunlight is absorbed by chlorophyll and converted into chemical energy in the form of electron carrier molecules like ATP and NADPH.

Light energy is harnessed in Photosystems I and II, both of which are present in the thylakoid membranes of chloroplasts.

In light-independent reactions (the Calvin cycle), carbohydrate molecules are assembled from carbon dioxide using the chemical energy harvested during the light-dependent reactions.