intro to cells (no endo)

What are the three main size groups students must compare in this lesson?

Viruses, prokaryotic cells, and eukaryotic cells; know their relative sizes, not just their names.

What is the general size order from smallest to largest?

Viruses are generally smallest, prokaryotic cells are larger, and eukaryotic cells are generally largest.

Why are cells small?

Small cells maintain a high surface-area-to-volume ratio, which helps them exchange materials efficiently.

What does SA:volume ratio stand for?

Surface-area-to-volume ratio: the amount of cell surface area compared with its internal volume.

What is surface area in a cell?

The area of the cell membrane available for exchanging substances with the environment.

What does volume represent in a cell?

The amount of internal space that requires nutrients and oxygen and produces waste.

Why is a high surface-area-to-volume ratio beneficial?

It provides more membrane area per unit of volume for obtaining nutrients and removing wastes.

What happens to SA:volume ratio when a cell increases in size?

The ratio decreases because volume grows faster than surface area.

Why can a cell not grow indefinitely?

Its volume can outgrow the membrane's ability to exchange enough materials to meet the cell's needs.

How does surface-area-to-volume ratio connect to cell survival?

A cell needs enough surface area to supply its internal volume with nutrients and remove wastes efficiently.

How do microvilli help small-intestine cells absorb nutrients?

Microvilli are fingerlike projections that increase the cell's surface area for nutrient absorption.

How does microvillus structure support its function?

The added membrane surface provides more area for absorbing nutrients from the intestine.

What application question about microvilli should you be able to answer?

Explain how their increased surface area improves nutrient absorption in the small intestine.

What are the two main types of cells?

Prokaryotic cells and eukaryotic cells.

What organisms have prokaryotic cells?

Organisms belonging to the domains Bacteria and Archaea.

What organisms have eukaryotic cells?

Animals, plants, fungi, and protists.

What are the five structures found in all cells according to the slides?

DNA as genetic material, cytoplasm or cytosol, plasma membrane, ribosomes, and cytoskeleton.

Why is DNA important to every cell?

It stores the genetic information needed to maintain and direct cellular activities.

What is the role of cytoplasm or cytosol?

Cytoplasm is the material inside the membrane; cytosol is its fluid component.

What is the role of the plasma membrane?

It forms the cell boundary and regulates what enters and leaves.

What is the role of ribosomes?

They make proteins.

What is the role of the cytoskeleton?

It helps support cell shape, organization, and movement.

What is the defining feature of a prokaryotic cell?

It lacks a nucleus; its DNA is located in a nucleoid region.

What is the nucleoid region?

The area of a prokaryotic cell where its DNA is located, without a surrounding nuclear membrane.

Are prokaryotic cells large or small?

They are very small compared with typical eukaryotic cells.

Do most prokaryotic cells have cell walls?

Yes. The slides state that most prokaryotic cells have cell walls.

How do bacterial and archaeal cell walls differ?

They are made of different substances, indicating early evolutionary divergence.

What are the defining features of eukaryotic cells listed in the slides?

They have a nucleus containing DNA, an endomembrane system, and membrane-bound organelles.

Which four groups of organisms are made of eukaryotic cells?

Animals, plants, fungi, and protists.

What is the nucleus?

A membrane-enclosed compartment that contains a eukaryotic cell's DNA.

What are membrane-bound organelles?

Specialized compartments enclosed by membranes that perform particular cellular functions.

What is the endomembrane system?

A system of internal membranes and associated organelles found in eukaryotic cells.

How do prokaryotic and eukaryotic cells differ in DNA location?

Prokaryotes have DNA in a nucleoid region; eukaryotes have DNA inside a nucleus.

How do prokaryotic and eukaryotic cells differ in internal organization?

Eukaryotes have membrane-bound organelles and an endomembrane system; prokaryotes lack these features.

How are prokaryotic and eukaryotic cells alike?

Both have DNA, cytoplasm or cytosol, a plasma membrane, ribosomes, and a cytoskeleton.

Why might an antibiotic target bacterial cell-wall synthesis?

Blocking cell-wall synthesis can prevent bacteria from building a functional wall needed for protection and structural support.

Why can bacterial cell walls be useful antibiotic targets?

Human cells do not have bacterial cell walls, allowing some antibiotics to target bacteria selectively.

What is the endosymbiont theory?

It proposes that mitochondria and chloroplasts evolved from bacteria that lived inside ancestral cells.

What does symbiosis mean?

A close relationship between organisms of different species.

What does endosymbiosis mean?

A symbiotic relationship in which one organism lives inside another organism.

What is an endosymbiont?

An organism that lives inside another organism in an endosymbiotic relationship.

What is the host in endosymbiosis?

The organism or cell that contains the endosymbiont.

What happened in the endosymbiont theory?

An ancestral host cell took in bacteria that survived inside it and eventually evolved into organelles.

Which two organelles are explained by endosymbiont theory?

Mitochondria and chloroplasts.

What is the role of mitochondria in modern eukaryotic cells?

They carry out most cellular ATP production through aerobic respiration.

What is the role of chloroplasts in modern eukaryotic cells?

They carry out photosynthesis in plants and algae.

What relationship is shown in the endosymbiont theory diagram?

An ancestral host cell and bacteria develop an endosymbiotic relationship; the bacteria eventually become organelles.

How should you explain what is happening in an endosymbiont theory diagram?

Describe the bacteria entering or living inside a host cell, their survival within it, and their eventual evolution into mitochondria or chloroplasts.

What major evidence supports endosymbiont theory?

Double membranes, prokaryote-like ribosomes, their own circular DNA, independent replication, and bacterial size.

How do mitochondrial and chloroplast membranes support endosymbiont theory?

Both have double membranes, consistent with an origin involving engulfed bacteria.

What is special about the inner membranes of mitochondria and chloroplasts?

They contain enzymes and electron transport chains resembling those in prokaryotes.

How do mitochondrial and chloroplast ribosomes support endosymbiont theory?

Their ribosomes resemble prokaryotic ribosomes more than eukaryotic cytoplasmic ribosomes.

What does it mean that mitochondria and chloroplasts have their own ribosomes?

They can synthesize some of their own proteins.

How does the DNA of mitochondria and chloroplasts support endosymbiont theory?

Both contain their own DNA arranged in circular chromosomes, as in prokaryotes.

How does independent replication support endosymbiont theory?

Mitochondria and chloroplasts replicate independently within cells through processes resembling prokaryotic reproduction.

How does the size of mitochondria and chloroplasts support endosymbiont theory?

They are approximately the same size as bacteria.

Which five evidence categories should you memorize for endosymbiont theory?

Double membranes, prokaryote-like ribosomes, their own circular DNA, independent replication, and bacterial size.

Do you need to memorize details about electron transport chains as evidence?

No. The slides emphasize the major evidence points rather than details such as electron transport chains.

What is mitochondrial DNA (mtDNA)?

DNA found inside mitochondria, separate from nuclear DNA.

According to the slides, which parent passes on mitochondrial DNA?

The mother; the presentation states that mtDNA is inherited only from the mother.

What are the three domains of life?

Bacteria, Archaea, and Eukarya.

Which domain includes animals, plants, fungi, and protists?

Eukarya.

Which two domains contain prokaryotic organisms?

Bacteria and Archaea.

What is the difference between Bacteria and Archaea highlighted in the slides?

Their cell walls contain different substances, indicating early evolutionary divergence.

What is cell theory?

The idea that living organisms are made of cells, cells are the basic units of life, and cells come from preexisting cells.

What is germ theory?

The idea that microorganisms can cause disease.

Which historical scientists are mentioned in the slides about microscopes?

Galileo, Hooke, and van Leeuwenhoek.

Which scientists are mentioned in the cell theory slide?

Schleiden, Schwann, and Virchow; the slide also mentions Remak.

Which scientists are mentioned in the germ theory slide?

Pasteur, Lister, and Koch.

Do you need to memorize the historical scientists' names for this lesson?

No. The slides say their names do not need to be memorized, although they might appear on the Biology SOL.

Do you need to memorize the germ-theory video details?

No. The slides explicitly say the video information is not required for memorization.

Do you need to label the typical animal and plant cell diagrams?

No. The slides state that labeling these diagrams is not required.

What is the overall connection between cell structure and function in this lesson?

Cell size, membranes, organelles, and internal organization help cells carry out essential functions efficiently.