Bio Ch. 11

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Define surface area

Define surface area

SA^cube(l x w x b) amount "covering" an object

Define volume

V^cube(l x w x h) amount of space inside object; how much space it takes up

What cells have the largest surface area to volume ratio?

Smaller cells

What cells have the smallest surface area to volume ratio?

Larger cells

Define information crisis

Too many demands placed on DNA

Define traffic problems

When the volume of a cell grows too fast relative to surface area, material exchange is insufficient

Describe cell division

Produces two daughter cells, cells must replicate DNA before division, diving to make more so smaller cells keep surface area to volume ratio high, can be either sexual or asexual

Describe asexual reproduction

A single parent produces genetically identical offspring, produces many offspring in short period, in stable environments genetically identical offspring thrive but if conditions change offsping not well adapted

Describe sexual reproduction

Involves fusion of two different parent cells, offspring inherit genetic information from each parent, relatively fewer offspring, growth takes more time, need to find a mate, in changing environments genetic diversity can be beneficial, offspring ma be less well adapted in current conditions

What has to occur before cell division?

Genetic material must be duplicated

What happens before cell division in prokaryotic cells?

DNA is packaged into a single, circular chromosome

What happens before cell division in eukaryotic cells?

DNA is packaged into multiple chromosomes, DNA wound around proteins called histones is called chromatin, precisely separated into two daughter cells during cell division

Describe the prokaryotic cell cycle

Undergo binary fission; cell duplicates, cell membrane indents, cell divides and two new cells form

Summarize the eukaryotic cell cycle

Cell grows, prepares for division, then divides to form two daughter cells

Describe interphase

Time in-between divisions, divided into G1 (cell growth), S (DNA replication), and G2 (preperation for mitosis) phases

Describe the M phase

Cell division occurs during M phase, includes prophase, metaphase, anaphase, and telophase

Describe prophase

Nucelus condenses and chromosomes become visible, spindle begins to form

Describe metaphase

Chromosomes line up at the center of the cell

Define sister chromatid

Pairs of chromosomes

Define centioles

Point where spindle fibers extend from

Define centomere

a point where the chromatids attach

Describe anaphase

Chromosomes move toward oppisite poles

Define Telophase

Cell begins to divide into daughter cells

Cytokinesis

In animal cells, cell membrane pinches in the center to form two daughter cells

List and describe the phases of mitosis

Interphase (includes G1- cell growth, S- DNA replication, G2- preparation for mitosis) which occurs in-between cell divisions, and M phase, which cell division occurs in (prophase- nucleus condences and chromosomes become visible, spindle begins to form, metaphase- chromosomes line up in center, anaphase- chromosomes move torwards oppisite poles, telophase- cell begins to divide into daughter cells, and cytokinesis (animal cells)- cell membrane pinches in center to form two daughter cells)

How does cell division relate to healing a bone

Cells at the edge of an injury are stimulated to divide rapidly, as an injury heals, the rate of cell division slows

Define cyclins

Proteins that regulate the cell cycle, the signal that controls the cell cycle, what tells a cell when to divide, when to duplicate chromosomes, when to enter another cell cycle stage

Describe how cyclins were discovered

Scientists found a protein in a cell undergoing mitosis, injecting protein into non dividing cell, mitotic spindle started to form

What are the two types of regulatory proteins

Internal and External regulators

Describe Internal regulators

Respond to events inside the cell

Let cell cycle proceed only when certain steps have already happened

Describe external regulators

Respond to events outside the cell

Direct cells to speed up or slow down the cell cycle

Define and describe apoptosis (me rn)

Process of programmed cell death, important role in structuring tissues during growth and development, cell undergoes series of controlled steps for self destruction

Describe cancer cells

Don’t respond to normal regulatory signals and in turn cell cycle is disrupted and cells grow and divide uncontrollably

Describe cancer formation

A cell begins to divide abnormally, produce a tumor and start to displace normal cells and tissues, cancer cells move to other parts of the body

What causes cancer?

A defect in genes that controll cell growth and division, in all cancers control over the cell cycle

Define differentiation

The process by which a cell becomes specialized, determines cell’s ultimate identity

Define stem cells

Specialized cells from which differentiated cells develop

Define totipotent cells

Cells that can develop into any type of cell in the body

Define pluripotent cells

Cells that are capable of developing into most but not all cell types

A human embryo forms into a blastocyst

A duck walks into a bar (idk but it seemed important so i put it)

Define multipotent

Limited potential to develop into many different types of differentiated cells

Describe adult stem cells

Multipotent, mainly found in bone marrow, hair follicles, also some in brain, heart, and skeletal muscle

Describe a bone marrow transplant (regenerative medicine)

Stem cells filtered from bone marrow removed from a patient’s hip, stem cells are injected into heart’s damaged area, environment of the heart stimulates injected stem cells to differentiate into new heart muscle cells

Describe the ethical issues in stem cells

Human adult stem cell research is rarely controversial because of willing donors. However, embryonic stem cells is controversial because arguments for and against involve ethical issues of life and death

Describe induced pluripotent stem cells

Breakthrough in 2007, human fibroblasts could be converted into cells that closely resembled embryonic stem cells, now widely used in research

Genes are added to adult cells, display properties similar to embryonic stem cells, now have capacity to develop into number of specialized cell types