Cells test 1 (Biology study guide)

Endomembrane System

a network of organelles in eukaryotic cells, including the nucleus, endoplasmic reticulum’s, Golgi apparatus, lysosomes, and vesicles, that work together to modify, package, and transport lipids and proteins.

Central Dogma of Biology

describes the flow of genetic information from DNA to RNA to protein through the processes of transcription (DNA to RNA) and translation (RNA to protein)

DNA

the molecule that contains the genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses, double helix.

RNA

a single-stranded nucleic acid that performs various functions in living cells and is the genetic material for some viruses

Protein

an essential nutrient made of amino acid chains that the body uses for growth, repair, and to build structures like muscle, bone, and skin

Gene

segment of your DNA that tells you how to make or do 1 thing.

Nucleus

the central, dense core of an atom containing protons and neutrons, or a membrane-bound organelle in eukaryotic cells that houses the cell's genetic material (DNA)

Nuclear Membrane

a double lipid bilayer that surrounds the nucleus in eukaryotic cells, separating the genetic material from the cytoplasm

Membrane bound

a specialized compartment in a eukaryotic cell that is enclosed by a phospholipid bilayer, which controls the movement of substances in and out of the compartment

Non-membrane bound

cell structures not enclosed by a membrane that perform specific functions

Phospholipid bailyer

a fundamental structure of biological membranes, comprising two layers of phospholipids arranged with hydrophilic heads facing outward and hydrophobic tails facing inward

Hydrophilic

“water loving” or attracted to water

Hydrophobic

"water-fearing" and do not mix with water, instead repelling it

Transcription

a biological process where a segment of DNA is copied into messenger RNA (mRNA), which is the first step in creating proteins

mRNA

It is a single-stranded molecule found in all living cells that plays a crucial role in protein synthesis by carrying genetic instructions from the DNA in the cell's nucleus to the ribosomes in the cytoplasm, where the proteins are made. 

Translation

reading a nucleic acid (mRNA) to make a Polypeptide chain  (protein)

Polypeptide Chain

a long chain of amino acids linked together by peptide bonds

Ribosome

a cellular machine that translates genetic information into proteins by linking together amino acids

rRNA

the primary component of ribosomes, which are the cellular machines that synthesize proteins

Large Subunit

one of the two components of a ribosome, which is responsible for protein synthesis. Its primary function is to catalyze peptide bond formation during translation

Small Subunit

small ribosomal subunit (SSU), a component of ribosomes responsible for reading the genetic message (mRNA) during protein synthesis

Rough Endoplasmic Reticulum

rough endoplasmic reticulum (RER), a vital organelle in eukaryotic cells. It is called "rough" because its surface is studded with ribosomes, giving it a rough appearance under a microscope

Smooth Endoplasmic Reticulum

a network of membranes within the cytoplasm of eukaryotic cells that lacks ribosomes. Its key functions include synthesizing lipids, detoxifying harmful substances like drugs and poisons, and metabolizing carbohydrates.

Secretory Vesicle

move or SECRETE  ”stuff” out of the cell (cell membrane)

Transport Vesicle

move “stuff” around the inside of the cell, from organelle to organelle.

Golgi Apparatus

a cellular organelle that functions as a packaging and processing center, modifying, sorting, and packaging proteins and lipids for secretion or delivery to other organelles

Cell Membrane

a barrier found in all cells that separates the cell's interior from the outside environment

Prokaryotic Cell

a simple type of cell that lacks a nucleus and membrane-bound organelles

Eukaryotic Cell

complex cells found in animals, plants, fungi, and protists, distinguished by a membrane-bound nucleus and other membrane-bound organelles like mitochondria and the endoplasmic reticulum

Exocytosis

Lactose

a disaccharide found in milk and dairy products

Lactase persistent

the ability to continue producing the enzyme lactase into adulthood

Lactose non-persistent

a condition where the body does not produce enough lactase

Lactose tolerant

the ability to digest lactose, a sugar found in milk and dairy products

Lactose intolerant

a condition where the body cannot fully digest lactose, the sugar in milk and dairy, leading to symptoms like bloating, gas, diarrhea, and abdominal cramps that usually appear 30 minutes to two hours after eating these products

3 components of original cell theory

1.All living things are made of at least one cell. 

2.The Cell is the basic unit of structure & function of all living things

3.Cells come from pre-existing cells.

Role of endomembrane

Modify, package, and transport proteins and lipids within a eukaryotic cell

Nuclear pores

Protein-lined channels in the nuclear envelope of eukaryotic cells that regulate the transport of molecules, such as proteins and RNA, between the nucleus and the cytoplasm

Nucleolus

Dark area in the nucleus, helps make the ribosomes and makes the rRNA

2 biomolecules that make up the structure of ribosome

ribosomal RNA (rRNA) and proteins

How does the location of ribosomes determine protein destination?

By separating proteins intended for use within the cell from those that are secreted or embedded in membranes

Describe reaction that lactase preforms

Lactase performs a hydrolysis reaction on the disaccharide sugar lactose by using a water molecule to break the bond between the two component sugars. This enzymatic action yields the two final simple sugars: glucose and galactose. These products are small enough to be absorbed through the wall of the small intestine into the bloodstream.

How do analyze if someone is lactase persistent?

Lactase persistence is the inherited trait that allows an adult to continue producing the lactase enzyme, enabling them to fully digest lactose (milk sugar). It is typically analyzed using a hydrogen breath test or genetic testing to confirm the effective breakdown and absorption of lactose.

How to draw a phospholipid bilayer

The phospholipid bilayer acts as the fundamental structural barrier of the cell membrane, separating the cell's internal environment from the outside. Its structure, with hydrophilic heads facing the water and hydrophobic tails forming the core, allows it to be selectively permeable, controlling which substances enter and exit the cell.

How to indicate if an organelle is membrane bound or non-membrane bound?

An organelle is membrane-bound if it is enclosed by a lipid bilayer separating it from the cytoplasm (e.g., nucleus, mitochondria), and non-membrane-bound if it lacks such a membrane and is exposed to the cytoplasm (e.g., ribosomes, cytoskeleton). You can indicate this by labeling or showing a surrounding membrane in diagrams.

Difference between prokaryote and eukaryote cells

Prokaryote cells:

• Do not have a nucleus; DNA is free in the cytoplasm.

• Lack membrane-bound organelles (e.g., mitochondria, ER).

• Generally smaller and simpler in structure.

Eukaryote cells:

• Have a nucleus that contains DNA.

• Contain membrane-bound organelles for specialized functions.

• Usually larger and more complex

Indicate what the “m” in mRNA stands for

messenger

Explain why mRNA is considered a quick, cheap copy of DNA

mRNA is considered a quick, cheap copy of DNA because it carries only the information needed to make a specific protein rather than the entire genome, so the cell doesn’t risk using or damaging the original DNA. It is also short-lived and easily produced, allowing the cell to rapidly respond to changing needs without committing long-term resources.

Role of a ribosome

Ribosomes are the cellular machines that synthesize proteins by linking amino acids together according to the instructions in mRNA. They are essential for cell growth, repair, and the production of enzymes and other functional proteins.

Role of amino acids in a cell

Amino acids are the building blocks of proteins and serve as precursors for hormones, neurotransmitters, and other important molecules. They also provide energy, regulate cell functions, maintain pH balance, and support cell growth and repair.

Role of polypeptide chains in a cell

Polypeptide chains are sequences of amino acids that fold into specific three-dimensional shapes to form proteins. These proteins carry out essential cellular functions, such as acting as enzymes, structural components, transporters, and signaling molecules.

Describe the way that lactase persistence occurs at the genetic level

Lactase persistence occurs due to a mutation in a regulatory region (enhancer) upstream of the LCT gene, which normally controls lactase production. This mutation keeps the LCT gene switched on after childhood, allowing continuous production of lactase throughout adulthood.

Relate the production of lactase to the function of the endomembrane system

Lactase is a protein enzyme produced in cells of the small intestine, and its production relies on the endomembrane system. The rough endoplasmic reticulum (ER) synthesizes the enzyme, the Golgi apparatus modifies and packages it, and vesicles transport it to the cell membrane, where it functions to break down lactose.

Distinguish between being lactase persistent and lactose intolerant

Lactase persistent individuals continue to produce the enzyme lactase into adulthood, allowing them to digest lactose without issues. Lactose intolerant individuals lose most lactase activity after childhood, leading to digestive discomfort when consuming dairy.