Biology Chapter: Building Proteins and Organelles

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Questions and Answers

What is the primary function of chloroplasts in plant cells?

Storage of genetic material

Respiration and energy release

Digestion of macromolecules

Synthesis of ATP and sugars (correct)

How do chloroplasts and mitochondria differ from other organelles?

They are not involved in energy production

They are part of the endomembrane system

They cannot reproduce independently

They have their own circular chromosome (correct)

What process transforms solar energy into chemical energy?

Photosynthesis (correct)

Protein synthesis

Fermentation

Cellular respiration

Which of the following statements is true regarding mitochondria?

Mitochondria can reproduce by pinching in two Signup and view all the answers

Why are chloroplasts typically green in color?

They contain chlorophyll, which absorbs blue and red light Signup and view all the answers

What organelle is responsible for pumping water out of a Paramecium cell?

Contractile vacuole Signup and view all the answers

What happens to animal cells in a hypertonic solution?

They lose water and can die Signup and view all the answers

What is the condition called when plant cells lose water and become flaccid?

Plasmolysis Signup and view all the answers

How do plant cells handle excess water without bursting?

Having a cell wall Signup and view all the answers

What is the result of an animal cell being in an isotonic environment?

It will remain unchanged Signup and view all the answers

Which organelle is primarily responsible for synthesizing proteins?

Ribosomes Signup and view all the answers

What is the main role of the Golgi apparatus in protein processing?

Modifying and folding proteins Signup and view all the answers

How do proteins typically get transported within the cell?

Via vesicles Signup and view all the answers

What is the primary function of the nucleus in relation to protein synthesis?

To protect DNA and provide instructions Signup and view all the answers

What modification can be made to proteins during processing?

Removing amino acids Signup and view all the answers

What is one function of glycoproteins in cells?

Addressing and transporting proteins to cell membranes Signup and view all the answers

What structure of the nucleus allows large macromolecules to pass through?

Nuclear pores Signup and view all the answers

Which is NOT a function of the endoplasmic reticulum?

Transporting vesicles Signup and view all the answers

What role do unsaturated fatty acids play in the composition of cell membranes?

They keep the membrane flexible. Signup and view all the answers

Which of the following molecules can cross the cell membrane through simple diffusion?

O2 Signup and view all the answers

What is a primary factor that affects water potential?

Types of solutes present Signup and view all the answers

In what way does cold adaptation affect the lipid composition of cell membranes?

It raises the percentage of unsaturated fatty acids. Signup and view all the answers

What happens to pressure potential when water is squeezed in a water balloon?

It increases. Signup and view all the answers

What defines a polar molecule, such as water?

It has charged regions. Signup and view all the answers

Which of the following is NOT a key function of a cell membrane?

Preventing all forms of transport. Signup and view all the answers

What are two variables that influence osmosis and the movement of water?

Solute concentration and physical pressure. Signup and view all the answers

What is the primary function of the nucleolus?

Ribosome production Signup and view all the answers

How does mRNA travel from the nucleus to the ribosome?

Through nuclear pores Signup and view all the answers

Which type of ribosome synthesizes proteins for export or for membranes?

Bound ribosomes Signup and view all the answers

What is one function of the smooth endoplasmic reticulum?

Detoxification of drugs Signup and view all the answers

What component combines to form functional ribosomes?

Proteins and rRNA Signup and view all the answers

What is the primary structure of ribosomes?

rRNA and proteins Signup and view all the answers

Which type of ribosome is suspended freely in the cytosol?

Free ribosomes Signup and view all the answers

What is involved in the synthesis of lipids in the cell?

Smooth ER Signup and view all the answers

What is one function of the rough endoplasmic reticulum?

Protein processing Signup and view all the answers

Which function is NOT associated with the endoplasmic reticulum?

DNA replication Signup and view all the answers

Study Notes

Building Proteins

DNA instructions are read to build proteins
Proteins are processed after being built
- Folding
- Modifying
- Removing Amino acids
- Adding other molecules (e.g. making glycoproteins for the cell membrane)
Proteins are addressed & transported

Organelles Involved

Nucleus protects DNA
- Has a double membrane fused in spots which create pores allowing large macromolecules to pass through
Ribosomes synthesize proteins
Endoplasmic Reticulum (ER) synthesizes & processes proteins
Golgi Apparatus processes & packages proteins
Vesicles transport proteins

Nucleus

Contains DNA in the form of chromosomes
DNA is wrapped around histone proteins
Contains the nucleolus where ribosomal subunits are assembled

Ribosomes

Made up of rRNA & protein
Have two subunits (large & small) which combine to form functional ribosomes
0.08 micrometers in diameter
Can be free or bound to the ER
- Free ribosomes synthesize proteins that function in the cytosol
- Bound ribosomes synthesize proteins for export, or for membranes

Endoplasmic Reticulum

Membrane connected to nuclear envelope and extends throughout the cell
Processes proteins
Manufactures membranes
Synthesizes and hydrolyzes many compounds

Smooth ER

Synthesizes lipids (oils, phospholipids, steroids, sex hormones)
Hydrolyses glycogen to glucose in the liver
Detoxifies drugs & poisons in the liver
Contains membrane-bound enzymes that can synthesize ATP

Chloroplasts

Function in photosynthesis
Generate ATP and synthesize sugars
Semi-autonomous organelles that can divide and move around the cell
Contain their own circular chromosome which directs synthesis of proteins by their own ribosomes

Mitochondria

Semi-autonomous organelles that can divide and move around the cell
Contain their own circular chromosome which directs synthesis of proteins by their own ribosomes

Water Potential

Water potential is the potential of water to move from one area to another.
Influenced by two variables:
- Solute concentration
- Physical pressure
High water potential allows water to move into the cell
Low water potential causes water to move out of the cell
- This can cause the cell to shrink

Managing Water Balance

Hypertonic solutions have a higher solute concentration than the cell
Hypotonic solutions have a lower solute concentration than the cell
Isotonic solutions have the same solute concentration as the cell

Diffusion across the cellular membrane

The cell membrane controls the flow of materials into and out of the cell.
The cell membrane is not impenetrable and allows for transport of many molecules
- In - Food, carbohydrates, amino acids, lipids, salts, oxygen, water
- Out- Waste, ammonia, salts, carbon dioxide, products

Membrane Fat Composition

The cell membrane is fluid and flexible
Higher % of unsaturated fatty acids in phospholipids increases membrane fluidity
Cholesterol in membrane plays a role in regulating membrane fluidity.

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Description

Explore the fascinating processes involved in protein synthesis and the key organelles that facilitate this crucial biological function. Learn how DNA instructions are translated into proteins, the role of ribosomes, and how the endoplasmic reticulum and Golgi apparatus contribute to protein processing and transport.