Homeotasis Cell structure and function 9.1-9.4 Flashcards
What two factors influence cell size?
Surface Area (SA), and Volume (V)
What is Surface Area?
Area covered by the plasma membrane.
What is volume?
The space taken up by the inner contents of the cell.
What is the formula for volume?
Length x Width x Height
What is the formula for Surface Area?
Length x Width X #of sides of the objec.
Cells with a higher SA:V ratio can sustain themselves more easily. (T/F)?
True
What is the cell cycle?
A cycle in which cells reproduce in a cycle of growing and dividing.
What are the 3 main stages of the cell cycle?
Interphase, Mitosis, Cytokinesis.
What is interphase?
Stage in which cell’s grow, it also carriers out cell functions and replicates its DNA.
How can stem cells help a patient coming to the doctor?
stem cells replace cells damaged by chemotherapy or disease or serve as a way for the donor’s immune system to fight some types of cancer and blood-related diseases
What is Mitosis?
The cell’s nucleus and nuclear material divide.
What is cytokinesis?
The cytoplasm divides, creating two new cells.
What are the three substages of interphase?
G1, S(synthesis), G2
Define chromasome?
structures that contain the genetic material.
What are structures that contain the gentic material?
Chromatin
What is the difference between prokaryotic and eukaryotic cell division?
Eukaryotic cells divide via the cell cycle and prokaryotic cells divide via binary fission
What is the main goal of mitosis?
to accurately separate the cell’s replicated DNA
What are the stages of mitosis?
Prophase Metaphase Anaphase Telophase
What are sister chromatids attached too?
Centromere
As prophase continues, spindle fibers, centrioles, and aster fibers form what?
A spindle apparatus
What happens in metaphase?
chromatids are pulled along the spindle apparatus toward the center of the cell and line up there.
What happens during anaphase?
chromatids pull apart, microtubules begin to shorten, chromatids then seperate, and the chromosomes move toward the poles of the cell.
What happens during telophase?
chromosomes arrive at the poles and begin to decondense, two new nuclear membranes form and the nucleioli reappear. The spindle apparatus also disassembles.
During cytokenesis what happens to animal cells?
microfilaments constrict/pinch off to form two cells
During cytokinesis what happens to plant cells?
a new structure called the cell plant forms between the two daughter nuclei.
What are cyclin?
Proteins that bind to enzymes called CDK’s
What are Cyclin dependent kinases?
Enzymes that bind with Cyclin to control activities during different stages of the cell cycle
What is Cancer?
Cancer is the uncontrolled growth and division of cells.
-Cancer results when cells stop responding to the controls of the
cell cycle.
-Cancer cells can kill an organism by crowding out normal cells,
resulting in the loss of tissue function.
What are carcinogens?
Substances that are known to cause cancer
What is apoptosis?
Programmed cell death, cells shrin and shrivel
What are stem cells?
Cells that can be directed to become a specialized cell.
What is cellular differentation?
the process by which an unspecialized cell develops into a specialized cell with a defined structure and function.
What are embryonic stem cells?
unspecialized cells that result after a
sperm fertilizes an egg.
Each embryonic stem cell has all the DNA needed to
develop into a wide variety of specialized cells.
What is a region that codes for the formation of proteins, which carry out most of the work for cells?
Genes
How many chromosomes are in each human body’s cell?
46: two sets of 23, each parent gives 23 chromosomes.
What are homologous chromosomes?
Chromosomes that make up a pair, one from each parent. Carry genes that control the same traits.
1 dad: 1 mom makes 1 pair of homologous chromosomes.
What are gametes?
sex cells that have half the number of chromosomes.
23 chromosomes
What does “n” represent in humans?
the # of chromosomes. So n=23
What is a haploid?
A cell with n number of chromosomes.
Cell with 23 chromosomes
What is fertilization?
When one haploid gamete combines with another haploid gamete.
What is a diploid?
A cell that contains 2n number of chromosomes.
(Cell with 46 chromosomes
What do sex chromosomes determine?
The individual’s gender.
How many autosomes are in a gamete?
22
What gender is a baby if it has one X chromosome and one Y chromosome?
The baby is a male
What gender is a baby that has two Y chromosomes?
Female
What is the purpose of meiosis?
To reduce the number of chromosomes.
It reduces the chromosome number by half through the seperation of homologous chromosomes.
When do gametes form?
During meiosis.
Where does meiosis occur?
In the reproductive structures of organisms that reproduce sexually, forming haploid gametes.
After meiosis how many chromosomes will the gametes contain?
n or 23 chromosomes
What happens in Interphase 1 of MEIOSIS?
Chromosomes replicate
chromatin condenses
What happens in Prophase 1 of MEIOSIS?
-Homologous chromosomes pair.
(Each chromosome consists of two chromatids)
- Crossing over produces the exchange of genetic information.
- The nuclear envelope breaks down.
- Spindles form.
What is the process of crossing over?
chromosomal segments are exchanged between a pair of homologous chromosomes
What happens in Metaphase 1 in MEIOSIS?
- Chromosome centromeres attach to spindles.
- Homologous chromosomes line up at equator.
What happens in Anaphase 1 of MEIOSIS?
-Homologous chromosomes separate and move to opposite poles of the cell.
What happens in Telophase 1 of MEIOSIS
- Spindles break down.
- Chromosomes uncoil to form two nuclei.
- The cell divides.
What happens in Prophase 2 in MEIOSIS?
- Chromosomes condense.
- Spindles form in each new cell.
- Spindle fibers attach to chromosomes.
What happens in Metaphase 2 of MEIOSIS?
Centromeres of chromosomes line up randomly at the equator of each cell.
What happens in Anaphase 2 of MEIOSIS?
- Centromeres split.
- Sister chromatids separate and move to opposite poles.
What happens in Telophase 2 of MEIOSIS?
- Four nuclei form around chromosomes.
- Spindles break down.
- Cells divide.
What are the products of MEIOSIS?
Four cells have formed.
Each nucleus contains a haploid number of chromosomes.
What is one thing that MEIOSIS provides?
Genetic Variation
In asexual reproduction what happens happens to the organism?
It inherents all of its chromosomes from a single parent, the individual is genetically identical
What are telomeres?
Chromosomes that end in protective caps that consist of DNA associated with proteins. A cap has a protective function for the structure of the chromosome.
What are karyotypes?
a type of micrograph in which the pairs of homologous chromosomes are arranged in decreasing size.
What is nondisjuction?
Cell division during which sister chromatids fail to separate properly
(occurs in autosomes and sex chromosomes)
What are autosomes?
chromosomes that are not sex chromosomes.
Humans typically have 22 pairs of autosomes.
In cytokinesis what happens to animal cells?
In animal cells, microfilaments constrict/pinch off to form two cells.
In cytokinesis what happens to plant cells?
In plant cells, instead of pinching in half, a new structure called the cell plate forms between the two daughter nuclei.
What is prophase?
the first and longest stage of mitosis.
Cell’s chromatin tightens/condenses into chromosomes.
What are some exmples of genetic variation?
Skin color, eye color, hair color, hand size, etc
