Chapter 2 Chromosome Transmission

What are the two major types of cells?

• Prokaryotes

• Eukaryotes

Which domains are prokaryotes?

Bacteria and Archaea

Which groups are eukaryotes?

• Protists

• Fungi

• Plants

• Animals

What is the biggest difference between prokaryotes and eukaryotes?

• Prokaryotes do not have a nucleus

• Eukaryotes do have a nucleus

Do prokaryotes contain a nucelus?

No

Do eukaryotes contain nucleus?

Yes

Where is the genetic material located in prokaryotes ?

In the nucleoid

What is the nucleoid?

The region where the DNA is found in prokaryotic cells

What type of chromosome do prokaryotes usually contain?

A single, circular chromosome

What type of chromosomes are found in eukaryotes?

Linear chromosomes

Where is most of the genetic material found in eukaryoytes?

Inside the nucleus

What surrounds the nucleus in eukaryotic cells?

A double membrane

What is a membrane-bound organelle?

A specialized structure surrounded by a membrane that performs a specific function

Which type of cell contains membrane-bound organelles?

Eukaryotic cells

Do prokaryotes contain membrane-bound organelles?

No

What membrane surrounds the cytoplasm of prokaryotes?

The plasma membrane

What is the function of the plasma membrane?

It regulates nutrient uptake and waste excretion

What is found outside the plasma membrane in prokaryotes?

A rigid cell wall

What is the function of a cell wall?

It provides structure and protection.

What additional structures may some prokaryotes contain?

• Outer membrane

• Flagellum

What is a flagellum?

A structure used for movement

Which organelle is responsible for ATP synthesis?

Mitochondria

What is ATP?

The cell's main energy currency.

Which organelle contains its own DNA?

Mitochondria

Which organelle plays a role in degradation of macromolecules?

Lysosomes

What is the function of lysosomes?

They break down macromolecules

Which organelle modifies and traffics proteins?

The Golgi apparatus

What is the function of the Golgi apparatus?

Protein modification and trafficking.

What does ER stand for?

Endoplasmic reticulum.

What are the two types of endoplasmic reticulum?

• Rough ER

• Smooth ER

If a cell lacks a nucleus, is it prokaryotic or eukaryotic?

Prokaryotic.

If a cell contains a nucleus, is it prokaryotic or eukaryotic?

Eukaryotic

If a cell has membrane-bound organelles, is it prokaryotic or eukaryotic?

Eukaryotic

If DNA is found in a nucleoid, is the cell prokaryotic or eukaryotic?

Prokaryotic.

If a cell contains a single circular chromosome, is it most likely prokaryotic or eukaryotic?

Prokaryotic.

If a cell contains linear chromosomes enclosed in a nucleus, is it most likely prokaryotic or eukaryotic?

Eukaryotic.

Are bacteria prokaryotes or eukaryotes?

Prokaryotes

Are archaea prokaryotes or eukaryotes?

Prokaryotes.

Are animals prokaryotes or eukaryotes?

Eukaryotes

Are plants prokaryotes or eukaryotes?

Eukaryotes.

Are fungi prokaryotes or eukaryotes?

Eukaryotes

Are protists prokaryotes or eukaryotes?

Eukaryotes

Do prokaryotes have DNA?

Yes. They have DNA, but it is not enclosed in a nucleus.

Is the nucleoid the same thing as a nucleus?

No.

A nucleoid contains DNA but is not enclosed by a membrane.

Do prokaryotes have membrane-bound organelles?

No.

Do eukaryotes have membrane-bound organelles?

Yes

What is the fastest way to distinguish a prokaryotic cell from a eukaryotic cell on an exam?

Does it have a nucleus?

• Yes → Eukaryote

• No → Prokaryote

What is the overall comparison between prokaryotes and eukaryotes?

Prokaryotes:

• No nucleus

• Single circular chromosome

• DNA in nucleoid

• No membrane-bound organelles

• Bacteria and Archaea

Eukaryotes:

• Have nucleus

• Linear chromosomes

• Membrane-bound organelles

• Protists, fungi, plants, and animals

What are chromosomes?

Structures within living cells that contain genetic material

What do chromosomes contain?

Genes

What is the main function of chromosomes?

To store and carry genetic information

What is the genetic material found in chromosomes?

DNA

What two major components make up chromosomes?

DNA and proteins

What is the role of DNA in chromosomes?

DNA is the genetic material.

What is the role of proteins in chromosomes?

Proteins provide organization and structure for the DNA.

What is chromatin?

The DNA-protein complex found in eukaryotic cells

In eukaryotes, what is the DNA-protein complex called?

Chromatin

What is another way to describe chromatin?

DNA packaged together with proteins.

Which contains the genes: DNA, proteins, or chromosomes?

Genes are found on DNA, and DNA is packaged into chromosomes

If a question asks for the structure that contains genes, what is the answer?

Chromosomes.

If a question asks for the genetic material itself, what is the answer?

DNA

If a question asks what helps organize DNA within chromosomes, what is the answer?

Proteins

How are chromosomes related to genes?

Chromosomes contain DNA, and DNA contains genes.

What is cytogenetics?

The field of genetics that involves the microscopic examination of chromosomes

What does a cytogeneticist study?

The chromosomal composition of a cell or organism

What is a cytogeneticist?

A scientist who examines chromosomes

Why do cytogeneticists examine chromosomes?

To study chromosome number and chromosome structure.

What can cytogenetics detect in individuals?

Abnormal chromosome number or abnormal chromosome structure.

Why is cytogenetics useful in medicine?

It can identify chromosome abnormalities.

Besides detecting abnormalities, what else can cytogenetics be used for?

Distinguishing between closely related species.

How does cytogenetics help distinguish closely related species?

Different species may have different chromosome numbers or structures.

If a question mentions looking at chromosomes under a microscope, what field is being described?

Cytogenetics.

What cellular structure is being examined in cytogenetics?

Chromosomes.

What is the relationship between chromosomes and chromatin?

Chromatin is the DNA-protein complex that makes up chromosomes.

What are the three key terms from these slides?

Chromosomes = structures containing genetic material

Chromatin = DNA + proteins

Cytogenetics = microscopic study of chromosomes

Are chromosomes made only of DNA?

No. Chromosomes are made of DNA and proteins.

Is chromatin the same thing as DNA alone?

No. Chromatin is DNA plus proteins.

What is the difference between chromatin and chromosomes?

Chromatin is the DNA-protein material; chromosomes are the organized structures made from that material.

What are the two major types of animal cells?

Somatic cells and germ cells

What are somatic cells?

Body cells other than gametes.

What is an example of a somatic cell?

A blood cell

What are germ cells?

Cells that produce gametes.

What are gametes?

Sperm and egg cells.

If a question mentions body cells that are not sperm or egg cells, what type of cells are being described?

Somatic cells.

If a question mentions sperm or egg cells, what type of cells are being described?

Germ cells (gametes).

Why are blood cells often used when preparing human chromosomes for study?

Because blood cells are easy to collect and can be induced to divide.

What drug is added to stop cells in mitosis during chromosome preparation?

Colchicine.

Why is colchicine added?

It disrupts spindle formation and stops cells in mitosis.

Why are cells stopped in mitosis?

Because chromosomes are highly condensed and easier to see.

At what stage are chromosomes easiest to observe?

Mitosis.

What happens to the sample after cells are stopped in mitosis?

It is centrifuged.

What is centrifugation used for in chromosome preparation?

To separate and concentrate cell

What part of the centrifuged sample contains the cells?

he pellet.

What happens to the supernatant?

It is discarded.

What solution are the cells placed in after centrifugation

A hypotonic solution.

Why are cells placed in a hypotonic solution?

To make the cells swell.

Why is swelling useful?

It spreads the chromosomes apart for easier viewing.

After swelling, what is done to the cells?

They are fixed, stained, and placed on a slide.

What is a karyotype?

An organized representation of the chromosomes within a cell.

How are chromosomes usually arranged in a karyotype?

From largest to smallest.