Biology 2 - Cell division

What are the pros of using embryonic stem cells?

• Can treat a wide range of diseases/problems -Painless procedure -Better to use cells than waste them

What is a multicellular organism?

Multicellular organisms are made of many cells and are much more complex.

What are the pros of using adult stem cells?

-Well-tried/ reliable technique -No ethical issues as adult gives consent/ doesn't kill donor -quick recovery for donor

Define mitosis.

The part of the cell cycle where the cell divides to make two new cells which are identical.

Define chromosome.

A structure containg one molecule of DNA. One chromosome contains many genes.

What are the cons of using adult stem cells?

-Hazards- involves operation -People may not want to be donors as it is painful -Few cell types can be formed/ fewer diseases treated

What is a unicellular organism?

Unicellular organisms' bodies are simply one cell.

Define cell cycle.

The series of stages during which the cell dives to make two new cells.

Define Embryo.

A very young multicellular organism, formed by fertilisation.

Define Stem Cells.

Cells that are undifferentiated.

Define Differentiation.

The process of becoming a specialised cell.

Define multicellular.

Describes organisms made of cells.

Describe and name the second stage of the cell cycle.

Mitosis -The cells line up across the middle of the cell. -Tiny fibres in the cell pull the copies of each chromosome to opposite sides -A new nuclear membrane forms around each set of chromosomes

Describe and name the third stage of the cell cycle.

Cytokinesis -The cytoplasm and cell membrane divides -Two identical daughter cells are created

How are cells from a meristem used?

To produce a large number of that crop which can be used for; -Food -Medicine -Repopulation

How many chromosomes does a baby have?

46

Why do cells grow before they divide?

They grow so when they spilt the embryo can grow as more cells divide.

Define unicellular.

Describes organisms formed of only one cell.

What happens during cell differentiation?

The cell gains extra subcellular structures.

Describe and name the first stage of the cell cycle.

Growth -The cell grows -Gains extra subcellular structures -The chromosomes are replicated

Give a brief summary on what happens during cell division.

-Nuclear membrane dissolves -DNA replicates -Chromosomes line up across the middle of the cell

• Identical chromosomes separate to opposite sides of the cell -Nuclear membrane forms around each set of chromosomes -Cytoplasm and cell membrane divide -Two identical daughter cells are formed

why is cell differentiation important when a baby develops from an egg?

-Different types of cells needed for different functions -Specialised cells make different organs/ parts of the body

What are the cons of using embryonic stem cells?

-Possible harm/death of an embryo -Long term effect unknown -Ethical issue/ embryo cannot give consent