Cells And Control Flashcards
(155 cards)
Most of the time where does DNA exist!?
In the nucleus as thin strands
When the cells containing nuclei are ready to divide what happens to the DNA!?
It copies itself then could and condenses to form chromosomes
What is DNA!?
Deoxyribonucleic acid. The material inside the nucleus of cells, carrying the genetic information of a living being.
What are chromosomes!?
The structure made of DNA that codes for all the characteristics of an organism.
How many chromosomes does each human body cell contain!?
46 chromosomes
How many chromosomes are in a pair!?
23
Each chromosome in a pair carries the same types of what!?
Genes
What is the 23rd pair!?
The sex chromosomes
Describe the pair of chromosomes in females….
the two chromosomes are identical in shape. These are X chromosomes. Females are referred to as XX
Describe the pair of chromosomes in a male…..
In males, one of the chromosomes is different in shape. This is a Y chromosome. Males are referred to as XY.
When do cells divide!?
Cells divide when:
an organism grows
an organism becomes damaged and needs to produce new cells for repair
organisms like bacteria reproduce asexually
What is essential that new cells contain!?
It is essential that any new cells produced contain genetic information that is identical to the parent cell.
What is the cell cycle!?
The events that lead to cell division and DNA replication.
What is the equation for length of time in a phase!?
Observed number of cells at that stage/total number of cells observed x total length of time of cell cycle
What is the definition of mitosis!?
A type of cell division which produces daughter cells identical to the parent.
Describe the process of mitosis!?
Mitosis is a type of cell division in which a diploid body cell copies itself and finally divides into two identical diploid daughter cells. The daughter cells are clones of each other. Every base pair of their DNA is identical.
What happens in the first phase of the cell cycle and what is it called!?
Interphase
The cell spends most of its life in this phase. The DNA in chromosomes copies itself ready for mitosis.
What happens in the second stage of the cell cycle !? And what is it called!?
Prophase
The DNA in chromosomes and their copies condenses to become more visible. The membrane around the nucleus disappears.
What happened in the third stage of the cell cycle !? And what is it called!?
MetaphaseChromosomes and their copies line up in the middle of the cell.
What happens in the fourth stage of the cell cycle and what is it called!?
Anaphase
Chromosomes and their copies are pulled to different ends of the cell
What is the fifth stage of the cell cycle!?
Telophase
New membranes form around the chromosomes at each end of the cell.
What happens it final stage of the cell cycle!?
CytokinesisThe cell membrane pinches in and eventually divides into two daughter cells.
What 4 stages of the cell cycle are part of mitosis!?
prophase, metaphase, anaphase and telophase.
When do cells use mitosis!?
Cells grow then divide by mitosis only when we need new ones. This is when we’re growing or need to replace old or damaged cells.