Biology - Exam 3 Study Guide

Do small Hydrophobic molecules directly pass through the cell membrane from higher to lower concentration?

Yes, they pass through the hydrophobic interior of the cell membrane from higher to lower concentration

Which energy source drives the facilitated diffusion of small, hydrophilic (polar) substances across the cell membrane?

Diffusion provides the energy for facilitated diffusion

What do carrier proteins transport?

Amino acids, disaccharides, monosaccharides, and nucleotides from higher to lower concentrations

What do channel proteins transport?

Small hydrophilic ions (ex: Ca++, Cl-, K+, H2O)

Is each carrier protein and channel protein specialized to transport a specific, small, hydrophilic chemical?

Yes, 300+ types of channel proteins are in the cell membrane

Does the facilitated diffusion of amino acids and glucose require a carrier protein or channel protein?

Carrier protein (ex: amino acids, monosaccharides)

Does the facilitated diffusion of Potassium (K) ions require a carrier protein or channel protein?

Channel Protein (ex: Ca++, K+)

Does the facilitated diffusion of Water (H2O) require a carrier protein other channel protein?

Water uses a channel protein called an aquaporin

What is an Aqauaporin?

Channel proteins that enable the facilitated diffusion of water molecules

Which chemical energy source do active transport proteins require?

ATP energizes active transport

Do active transport proteins move substances across the cell membrane from higher to lower concentration?

Yes, it moves molecules from lower to higher concentration

Which active transport proteins enable cancer cells to export anti cancer drugs and also enable pathogenic bacteria to export antibiotics?

Multi-drug resistant proteins

Define Diffusion

The movement of molecules from higher to lower concentration, and the supplier of energy for active transport

Do your cells use diffusion as an energy source to drive the facilitated diffusion of atoms and some small molecules across the cell membrane?

Yes, diffusion provides the energy for facilitated diffusion

What are vesicles?

Transport compartment that contain one or more substances

Which process do beta cells of the pancreas use to simultaneously export multiple copies of insulin stored in vesicles?

Exocytosis enables cells to export substances, while Endocrine cells release hormones (such as insulin)

Which process enables cancer cells to export multiple copies of growth factors stored in vesicles to stimulate new blood vessel formation?

Exocytosis enables cells to export substances that can’t be exported used carrier or channel proteins

Why do your cells require endocytosis?

Cells can’t use carrier, channel, or active transport proteins to move larger substances. Endocytosis enables the cell membrane to engulf larger substances and import them

What are some functions of pinocytosis?

Imports extracellular fluid, retrieves ions & nutrients, maintains homeostasis, helps immunity, removes debris, and recovers useful molecules in kidneys

What is the function of receptor‑mediated endocytosis?

Enables cells to import specific large particles in a regular manner (ex: Antibodies, HDL/LDL lipoproteins, Hormones, and Transferrin (iron transport)

Which process enables your macrophages to import bacteria and viruses for destruction?

Phagocytosis enables your white blood cells to import and eliminate foreign invaders

Which three types of protein filaments form the cytoskeleton?

Actin filaments, Intermediate filaments, and Microtubules

Which motor proteins use the energy of ATP to move along actin filaments (microfilaments)?

Actin filament and myosis motor protein interaction enable Muscle Cell Contraction

Which motor proteins use the energy of ATP to move along microtubules?

Dyneins and Kinesis

Which proteins enable motor proteins to attach to the substances they transport?

Adapter proteins. They connect motor proteins to cellular particles, organelles, and transport vesicles.

Describe the Central Dogma of Molecular Biology.

Genetic code info is stored in DNA, Transcription transfers to mRNA, and Translation converts into the protein the gene encodes

Define the genetic code and the codon.

The genetic code consists of the genetic alphabet (A, C, G, T)

Each Condon consists of 3 Nucleotides. They are also called triplets

Other than minor exceptions, does all life use the same genetic code?

Yes, the genetic code is universal

Does the cell perform transcription to access gene instructions when it needs to make the protein the gene encodes?

Yes, transcription enables cells to access the instructions in a gene to make the protein the gene encodes

Which enzyme performs transcription?

RNA polymerase makes mRNA during transcription

Which type of RNA does this enzyme synthesize during transcription?

mRNA

Does RNA polymerase read the template strand or the coding strand?

It reads the Nucleotide Sequence of the template , or non-coding DNA strand, to make a copy of the coding strand

Which monomers does RNA polymerase link together during elongation?

Ribonucleotides (A, C, G, U)

Is mRNA a copy of the gene’s template/coding strand?

Yes, it makes a copy by reading the template/coding strand

Does mRNA contain thymine or uracil?

Uracil replaces Thymine in mRNA

What defines the initiation phase?

When the cell receives the signal, general transcription factors bind to the promoter and to RNA polymerase

What defines the elongation phase?

RNA polymerase beings to synthesize mRNA at 1+ bonds. It also bonds the Ribonucleotides together.

What defines the termination phase?

The stop site sequence is AATAAA. RNA polymerase moves 10-35 nucleotides past and it releases the mRNA

Do some promoters contain the TATA box sequence?

Yes

To which part of the gene do the six general transcription factors bind during initiation

The Promotor

Which proteins align and activate RNA polymerase at the promoter?

General transcription factors bind to RNA polymerase to form the initiation complex

At which nucleotide sequence does RNA polymerase begin transcribing the gene?

At the transcription start site, which is called the 1+ nucleotide

At which nucleotide sequence does RNA polymerase stop transcribing the gene?

The stop sequence is AATAAA