Unit 7 notes 1 and 2 Flashcards
Why do cells want to be small?
- They want a big surface area to volume ratio
- It is easy to move things in and out of the cell across the cell membrane
What happens when a cell becomes to large?
The cell divides into 2 cells
- These 2 cells are called daughter cells
Define cell division
The process where a cell divides into 2 new cells
define the Cell cycle
A cycle of cell growth and division
- Cell grows, prepares to divide, and then divides
What are the 2 major parts of the cell cycle?
Interphase and Mitosis
What are the steps of the Interphase?
- G1
- S phase
- G2
How much of their time do adult mammal cells spend in the Interphase
90%
what happening during the G1 phase?
Cell grows and proteins are made
What happens during the S phase?
Cell copies it’s chromosomes and DNA is made
What happens during the G2 phase?
Cell prepares to divide
What can control cell growth?
Growth factors: Special proteins that speed up or slow down the cell growth and division
When would you want to increase cell growth?
- Healing a wound
- Embryonic growth (growing a baby)
Define cancer
Uncontrolled cell division
- Caused by defects in the proteins
Define carcinogen
Any environmental agent that causes cancer
What are examples of carcinogens?
Radiation, Smoking, Tobacco
What is a Genetic factor?
Genes you can inherit that could increase your risk of cancer
How do cancer cells spread?
Cancer cells from masses the tissues called tumors, that block nutrients from getting to healthy cells
Define metastasis
A process where cancer enter the circulatory system (blood) and spreads
Benign tumors
Not cancerous, do not spread to other parts of the body
Malignant tumor
Cancerous, hamrful tumors
How can you body stop a cell from becoming cancerous?
During the cell cycle the cell goes thourgh checkpoints, these checkpoints stop unhealthy cells from entering Mitosis
What do the check points check for during the interphase?
- Does the cell need to divide
- Is the cell large enough to divide
- Does the cell have enough resources to survive
- Is the DNA damaged
- Has the DNA been replicated properly
What happens if a cell does not divide, but nothing is wrong with it?
G0 phase - A phase of the cell cycle where a cell carries out it’s normal cell functions but is not preparing to divide
Define Apoptosis
A process of programmed cell death
- A cell with destroy itself if it does not pass a checkpoint during the interphase
What type of chromosome is in prokaryote cells?
One circlular chromosome
How is DNA stored in prokaryote cells?
floating in the cytoplasm
What happens during binary fission?
The cell duplicates its DNA and the cell divides into 2 new cells
What type of cells go through binary fission?
prokaryotic
How is DNA stored in eukaryote cells?
Wrapped into chromatins and chromosomes
Define chromatin
Long strands of DNA wrapped around proteins called histones
- Chromatin wraps up into chromosomes
define chromosomes
structures that are packages of DNA
What are somatic cells?
body cells
How many Somatic chromosomes do you have?
46 chromosomes or 23 pairs
What are gametes?
sex cells
How many gametes do you have?
23 chromosomes/no pairs
Define sister chromatids
2 halves of the chromosome, each half is an exact copy of the other half due to DNA replication
Define centromere
A structure that holds the 2 sister chromatids together
What are the phases of mitosis?
Prophase, Metaphase, Anaphase, Telophase
What happens during the prophase?
- Chromatin coils up into visible chromosomes (condenses)
- Nuclear membrane begins to disappear
- centrioles move to opposite sides of the cell
- Spindle fibers begin to from
Define centriole
Small circular structures that are attached to the spindle fibers
Define spindle fibers
Threadlike structures that attach to the chromosomes
What happens during the metaphase?
- spindle fibers attach to the centromeres of the chromosomes
- chromosomes line up in the middle of the cell
What happens during anaphase?
- Sister chromatids move towards opposite sides of the cell
What happens during the Telophase
- Nuclear membrane reforms
- chromosomes begin to unwind
- 2 new cells start to form that are identical
What happens during cytokinesis?
-cytoplasm divides
- occurs after mitosis
What happen during cytokinesis in animal cells?
-cell membrane is pulled in toward that center of the cell until is splits
What is a cleavage furrow?
The crease that is created during cytokinesis in animal cells
What happens during
