Cell Cycle, Mitosis, and Stem Cells: Key Concepts for Biology

What are chromosomes made of?

Highly coiled strands of DNA.

How many chromosomes do humans have?

46 chromosomes, found in 23 pairs.

What is the role of chromosomes in diploid organisms?

They are normally found in pairs, one from each parent.

What happens to chromosomes before a cell divides?

The genetic material is doubled, resulting in X-shaped chromosomes.

What is mitosis?

A stage in the cell cycle when the nucleus divides.

What occurs during the growth phase of the cell cycle?

The genetic material is doubled and subcellular structures increase.

What are chromatids?

The two strands that make up an X-shaped chromosome after replication.

What is cytokinesis?

The process of dividing the cytoplasm and cell membrane to form two daughter cells.

What is the significance of mitosis in multicellular organisms?

It is essential for growth and development, allowing cells to divide and increase in number.

What happens to the number of ribosomes and mitochondria during the growth phase?

The number of ribosomes and mitochondria increases.

What is the first step in the process of mitosis?

Chromosomes replicate, resulting in X-shaped chromosomes.

How are chromatids separated during mitosis?

They are pulled to opposite ends of the cell.

What forms around each new group of chromosomes after mitosis?

A new nucleus.

What is the result of cytokinesis?

The formation of two genetically identical daughter cells.

What is the structure of chromosomes when a cell is not dividing?

Chromosomes are uncoiled and appear as strands of thread.

What is the total number of chromatids in a human cell before mitosis?

92 chromatids (46 chromosomes doubled).

What is the process of fertilization in human reproduction?

A sperm cell fertilizes an egg cell, forming a zygote that divides by mitosis.

What is the overall sequence of the cell cycle?

Growth phase, mitosis, and cytokinesis.

What should you look for in micrographs of cells in different stages of mitosis?

Identify cells actively dividing by their distinct chromosome structures.

What is an exception to the presence of chromosomes in body cells?

Red blood cells lose their nuclei and therefore have no chromosomes.

What happens to chromosomes during the process of cell division?

They fold up into 'worm-like' structures.

What is the importance of cell division for an embryo?

It allows the embryo to grow in size as cells divide and differentiate.

What is the significance of the number of chromosomes in different species?

Different species have different numbers of chromosomes in their nuclei.

What is the role of mitosis in multicellular organisms?

Mitosis is important for growth and development, allowing cells to divide and increase in number.

What happens when a sperm cell fertilizes an egg cell?

The resulting zygote cell divides by mitosis to form an embryo.

What are the three overall stages of the cell cycle?

Growth phase, Mitosis, and Cytokinesis.

How can you estimate the duration of each stage of the cell cycle?

By observing the number of cells in each stage of the cell cycle.

What are specialized cells?

Cells that have a particular structure and function, formed through differentiation.

How many specialized cell types are there in the human body?

About 250 specialized cell types.

What is a stem cell?

An undifferentiated cell capable of dividing and giving rise to many more cells of the same type.

What is the role of embryonic stem cells?

They help form all the different tissues and organs needed during development.

What is the function of adult stem cells?

To replace lost cells due to damage and produce new cells for growth.

What are meristem cells in plants?

Unspecialized cells that can differentiate into various types of plant cells.

What is therapeutic cloning?

The process of creating an embryo with the same genes as the patient for stem cell therapy.

Why are stem cells from therapeutic cloning not rejected by the patient's body?

Because they have the same genetic makeup as the patient, eliminating immune rejection.

What are the potential medical uses of stem cells?

To repair damaged organs and treat diseases like diabetes and paralysis.

What is the advantage of cloning rare plant species?

To protect them from extinction and maintain biodiversity.

How can plant stem cells be used economically?

They can produce clones of plants quickly and at a low cost.

What is a disadvantage of cloning plants?

Clones have low genetic diversity.

What environmental benefit does cloning crop plants provide?

It reduces the need for chemicals such as pesticides.

What is the significance of cell differentiation?

It allows stem cells to develop into specialized cells with specific functions.

What visual characteristics indicate cells that are not actively dividing?

Their chromosomes will be unraveled and appear non-distinct, like strands of thread.

What is the importance of understanding the stages of mitosis for exams?

Recognizing and describing stages in micrographs can be crucial for exam success.

What is the main purpose of stem cell technology in medicine?

To repair or replace damaged tissues and organs.

What is the key difference between embryonic and adult stem cells?

Embryonic stem cells can differentiate into more cell types than adult stem cells.

What is the role of stem cells in the bone marrow?

To continually produce new blood cells throughout life.

Why are embryonic stem cells considered valuable in research?

They can differentiate into most types of specialized cells.

What is the significance of the growth phase in the cell cycle?

It involves chromosome doubling and an increase in subcellular structures.

What ethical concerns are associated with embryonic stem cell research?

The moral implications of using embryos for research and therapy.

What is the role of chromosomes in cell division?

They must be doubled before a cell can divide.

What happens during the growth phase of the cell cycle?

The genetic material is doubled and subcellular structures increase.

What occurs during cytokinesis?

The cytoplasm and cell membrane divide, forming two new daughter cells.

What is the result of mitosis?

Two genetically identical daughter cells.

What happens to red blood cells in terms of chromosomes?

They lose their nuclei and therefore have no chromosomes.

What is the total number of chromatids in a human cell before division?

92 chromatids (46 chromosomes doubled).

What does the term 'diploid' refer to?

Organisms that have pairs of chromosomes in their body cells.

What is the significance of the 'X' shape of chromosomes?

It indicates that the chromosomes have been replicated and are ready for division.

What is the role of mitosis in human reproduction?

It allows the zygote to divide and form an embryo.

What is the purpose of estimating the duration of each stage of the cell cycle?

To understand how long each stage lasts based on the number of cells in each stage.

What happens to specialized cells that can divide by mitosis?

They produce daughter cells of the same type and lose the ability to differentiate into other types.

What are stem cells?

Undifferentiated cells capable of dividing and giving rise to many more undifferentiated cells.

What is the primary function of adult stem cells?

To replace lost cells due to damage or to produce new cells for growth.

How do stem cells in plants differ from those in animals?

Plant stem cells can be easily obtained from meristems without ethical objections.

What potential diseases could stem cell treatment help cure in the future?

Diseases such as diabetes and paralysis.

What is a benefit of cloning rare plant species?

To protect them and maintain biodiversity.

How can cloning benefit agriculture?

By producing large numbers of identical plants with special features like disease resistance.

What is the significance of stem cell technology in medicine?

It could enable the repair of damaged organs and the growth of new tissues.

What is the main advantage of using plant stem cells for cloning?

Cloning can be done quickly and economically.

What is the role of bone marrow in adult stem cells?

To continually produce new blood cells throughout life.

What is differentiation in the context of stem cells?

The process by which stem cells develop into specialized cells.

What is the best source of embryonic stem cells for therapeutic cloning?

A 5-day old embryo.

How do scientists use embryonic stem cells in research?

To encourage differentiation into specialized cells for medical applications.

What is the potential environmental benefit of cloning crop plants?

It reduces the need for chemicals like pesticides.