Cell Membrane and Transport

Flashcards about cell membranes, proteins, and transport

What are the two types of large proteins found in cell membranes?

Integral and Peripheral proteins

Which type of protein is embedded within the cell membrane?

Integral proteins

Which type of protein is attached to the cell membrane but not embedded in it?

Peripheral proteins

Can peripheral proteins attach to both the extracellular and intracellular sides of the membrane?

Yes

What is the main difference between channel and carrier proteins?

Channel proteins have an open pore, while carrier proteins bind and escort specific molecules.

Are channel proteins specific for the molecules they transport?

Yes, channels are specific for certain molecules.

How does a carrier protein facilitate transport?

By grabbing onto a specific molecule and escorting it across the membrane.

How is 'docking' defined in the context of membrane proteins?

A loose, temporary attachment, serving as an anchor.

How is 'binding' defined in the context of membrane proteins?

A firm, specific attachment, like a lock and key.

Is binding a strong or weak attachment?

Strong and longer attachment

Is docking a strong or weak attachment?

Loose and temporary attachment

What is the primary function of a docking protein?

To serve as an anchor for other proteins.

What type of molecules do binding proteins typically attach to?

Chemical messengers (hormones)

Do docking protein attachments usually result in action/cellular response?

No, docking is just a site to anchor.

What are binding-type proteins often called?

Receptors

What is the role of a receptor?

To transmit a signal from a messenger to the cell causing a cellular response.

What is signal transduction?

The process by which a receptor transmits a signal to the cell, causing a response.

Describe the structure of a receptor protein in the cell membrane.

It spans the entire membrane, with parts exposed to both the extracellular and intracellular environments.

What is a signaling cascade?

A sequence of activation of other molecules inside the cell for the cell to respond.

For the digestion process, where are docking proteins popular?

In the digestive tract

What role do docking proteins play in the digestive tract?

They anchor enzymes involved in digestion.

What is chyme?

A slurry of nutrients resulting from food broken down in the stomach.

Why must nutrients be broken down to their single molecules for?

For cellular uptake and transport to blood.

What is the function of lipase?

It breaks down lipids.

Following digestion, where are nutrients typically transported after being absorbed by cells?

To the liver via the bloodstream.

Are immune components found in mother's milk after the first 24hours?

Yes

What is colostrum?

The first milk produced by a mother, rich in immune cells and nutrients.

How long is colostrum made by the mother?

About 24 hours

Why is the timing of colostrum consumption important for newborns?

The newborn's gut is open (more permeable) for the first 24 hours, allowing easy uptake of antibodies and nutrients.

What is 'gut closure'?

The process where tight junctions fully form in the newborn's intestines, reducing permeability after approximately 24 hours.

What are tight junctions?

Adhesion proteins that sew one cell membrane to another, preventing molecules from slipping past cells.

What is a gap junction?

Large proteins that form a channel between cells, allowing transfer of cytosol and communication.

What can pass through a gap junction?

Cytosol, nutrients, and communication signals.

Why is it dangerous for gametes (sperm and oocytes) to come into contact with blood?

The immune system would not recognize them, and their immune system could destroy them because they only have half the amount of chromosomes.

How do gametes receive essential nutrients?

Through gap junctions from surrounding cells that are in contact with blood.

What are the main purposes of tight junctions?

To help create the tissue its shape, hold it together, but also to get the goodies from the mother's colostrum from the baby.

What is cell type recognition?

The process by which cells identify themselves using large proteins in the cell membrane.

What do large proteins on cell surfaces identify?

Species, gender, tissue type, and individual characteristics.

What is enzimatic activity?

Speeds up chemical reactions of molecules.

Why is cell-type recognition important?

It prevents the immune system from attacking the body's own cells and ensures the correct tissue organization.

What are the two main types of transportation across the cell membrane?

Passive and active transport

What is passive transportation?

The process that uses no energy is consumed as the molecule passes from the extracellular environment into the intracellular environment, or vice versa.

What is active transport?

When energy is used to transport molecules across the plasma membrane.

What is diffusion?

The passive movement of solutes.

What factors affect the rate of diffusion?

Concentration gradient, size of the molecule, charge, and temperature.

How does the concentration gradient affect the rate of diffusion?

A greater concentration difference leads to a faster rate of diffusion.

How does the size of the molecule affect the rate of diffusion?

Smaller molecules diffuse faster than larger ones.

What is facilitated diffusion?

The solute passively crosses the membrane with no energy conserved.

What is GLUT?

Glucose transporter

What is the function of the liver, related to facilitated diffusion and glute?

If the body is deficient in glucose, the liver will synthesize glucose and release it into the blood.