Biology Chapter 5 Study Guide

Sexual reproduction

Sexual reproduction

reproduction between two organisms that results in a genetically mixed organism

Asexual reproduction

reproduction that a single parent produces offspring that are genetically identical to the parent

Binary fission

a form of asexual reproduction in single-celled organisms by which one cell divides into two cells of the same size

Apoptosis

programmed cell death

External factors

outside the cell - include messages from nearby cells and from distant parts of the organism’s body

Internal factors

inside of the cell - kinases and cyclins

Centromere

uncoiled DNA

Telomere

the region at the tip of a chromosome made of repeating DNA sequences

Chromosome

structures in the nucleus that are made up of DNA and protein

Chromatin

substance that composes chromosomes; consists of specific proteins DNA and small amounts of RNA

Zygote

result of two gametes uniting

Gametes

a haploid reproductive cell that unites with other to form a zygote

Cancer

uncontrolled cell division

Malignant

cancerous tumor, cells break away and spread to other parts of the body harming the organism

Benign

having no dangerous effect on health referring to abnormal growth of cells that are not cancerous

What is the first stage of the cell cycle?

interphase

What is the second stage of the cell cycle?

Prophase

What is the third phase of the cell cycle?

Metaphase

What is the fourth phase of the cell cycle?

Anaphase

What is the fifth stage of the cell cycle?

Telophase

What is the sixth stage of the cell cycle

Cytokinesis

What happens in interphase?

Longest part of the cell cycle and everything doubles

What happens in prophase?

spindle fibers appear an the chromosomes become visible

What happens in metaphase?

chromatids line up in the middle of cell

What happens in anaphase?

chromatids separate and begin to move to opposite ends of the cell

What happens in telophase?

Two nuclei form. Chromosomes have moved to opposite poles

What happens in cytokinesis?

The cell membrane completely splits and becomes two daughter cells

What are the key checkpoints?

Between G1 and S - check for DNA damage

Between G2 and M - check cell size and that DNA is copied

Before metaphase - check that spindle fibers are attached

What is the end product of mitosis/cytokinesis?

two identical daughter cells (diploid)

What is the end product of asexual reproduction?

two identical daughter cells (diploid)

What are the stages of mitosis?

prophase, metaphase, anaphase, telophase

What is the difference between mitosis in plants and animal cells?

plant cells - during mitosis the plant creates a cell wall between the new cells

animal cells - cleavage furrow forms and pinches the cell wall and the cell membranes splits apart

What is a carcinogen?

something that causes cancer

What is an example of a carcinogen?

alcohol, nicotine, UV rays

What is budding?

when an organism makes a growth off of itself then breaks off and becomes a new organism

example - sponges

What is binary fission?

one cell divides into two cells of the same size

example - amoeba

What is fragmentation?

organism breaks into pieces and those pieces become new organisms

example - starfish

What is vegetative reproduction?

stem, branch, or root becomes a new organism

example - strawberries

What is hermaphrodite?

when an organism has both sex organs

example - snails

Advantages of sexual reproduction

has genetic variation

adapts to changing environments

Disadvantages of sexual reproduction

requires two organisms

takes time

takes energy

Advantages of asexual reproduction

only needs one organism

faster

Disadvantages of asexual reproduction

exact same organism is produced

What is differentiation?

cells specialize in a job

When does differentiation occur?

occurs during development (embryo)

What are stem cells and their importance?

undifferentiated cells that can turn into any cell - important since they can do different jobs and for medical purposes

Advantages of adult stem cells

can be taken from patient

grown in culture

risk of rejection is low

avoids ethical issues

Disadvantages of adult stem cells

few in number

difficult to isolate

risky to grow

contain more DNA abnormalities

Advantages of embryonic stem cells

Can grow indefinitely

can cure a lot of things

Disadvantages of embryonic stem cells

can cause tumors if unchecked

body can reject the foreign tissue

What is a immortal cell?(Henrietta Lacks)

cell that double in volume every 20 to 24 and have the potential to be immortal if they were fed the right nutrients

What medical problem did Henrietta Lacks have?

cervical cancer

What baffled scientists about Henrietta Lack’s cells?

her cells doubled in volume every 20 to 24 - has the potential to be immortal if they were fed the right nutrients

What are 3 scientific discoveries that came from Henrietta Lack’s cells?

• her cells became an effective tool for growing large amounts of poliovirus

• used her cells to develop a cancer research method

• used her cells to study the impacs of x-rays on human cell growth

What are some ethical issues about using her cells?

• informed consent

• medical records privacy

• communication with tissue donors

• research participants

What happens in G2?

prepare for mitosis and double in size

What happens in G1?

cell grows in size

What happens in S (synthesis)

DNA copies