Chapter 10 - Cell Reproduction Flashcards
Sexually reproducing organisms start life as a single cell called…
A zygote
Non sexual cells reproduce through what?
Cell division
The result of division of a single parent cell to the production of two genetically identical what cells?
Daughter cells
All of a cells DNA is called it’s….
Genome
The genome of prokaryotes have what characteristics? Where are they found in a prokaryotic cell?
They are double stranded DNA molecules in the form of a loop, and found in an area called the nucleoid region
Some prokaryotes have small loops of DNA called…
Plasmids
Eukaryotic genomes consist of what shape? What are they called?
Linear pieces of DNA called chromosomes
Sex cells are also called
Gametes
What is the difference in Number of chromosomes from gametes to somatic cells? For example human cells
Gametes have half the number of chromosomes of somatic cells, for example human gametes have 23, somatic has 46
Body cells contain 2 matched or homologous sets of chromosomes while sex cells have just one set of chromosomes, what are these 2 denoted as in genetics?
Body cells containing 2 matched or homologous sets of chromosomes are denoted as diploid (2n), while human cells with just one set of chromosomes are haploid (n)
Upon fertilization each gamete contributes one set of chromosomes in a diploid cell which has matched pairs of chromosomes called…
Homologous chromosomes
Homologous chromosomes are the same length and have the same genes in exactly the same location called…
The locus
What are the functional units of chromosomes and determine specific characteristics by coding for specific proteins?
Genes
What are the possible variants of the specific characteristics coded by genes?
Traits
A complete gene is made up of how many alleles?
2 (1 from each parent)
Alleles can be identical or not, what are they called in each case?
Identical (homozygous), different (heterozygous)
What are the only homologous pair of the 23 chromosomes to have genes for different characteristics at the same locus?
The X and Y chromosomes
What is at the first level of compaction in chromosomes?
The DNA double helix is wrapped around a core of 8 histone proteins along the entire length of the chromosome now called chromatin,
The bead like DNA/histone complexes are called what? How much larger would they be without histones?
They are called nucleosomes, they would be 7 times larger without histones
What is the second level of compaction in chromosomes?
The nucleosomes and the linker DNA coil into 30nm fibers, shortening the chromosomes by about 50x
What is level 3 of compaction in chromosomes? What is the purpose of this level?
A variety of fibrous proteins further condense the chromatin in a non dividing cell, this makes sure no DNA overlaps
If a cell is to divide it enters what phase of interphase?
The S-phase where replication of the entire chromosome occurs
Replicated sister chromatids bind together with cohesion proteins, the closest point being where?
The centromere
What are the 2 major phases of the cell cycle?
Interphase, and the mitotic phase
If cytokinesis does not occur when it needs to what happens?
Multiple nuclei is produced
Overall what happens in interphase? What three stages of interphase is there?
The cell undergoes growth processes while preparing for cell division. The 3 stages include G1, S, and G2
What happens in G1 phase of interphase?
Called the first gap it is where little change is visible in microscope, but much occurs biochemically like chromosomal structure is completed, cell reaches its full size, energy reserves are accumulated and DNA is in its chromatin state
What happens in the S phase of Interphase?
DNA synthesis happens here it produces two identical chromatids from each DNA strand, the centrosome is duplicated which will give rise to the mitotic spindle which will move the chromatids and help organize cell division
What happens in the G2 phase of interphase?
Now in the second gap, energy stores are replenished, proteins necessary for chromosome manipulation and movement are duplicated, the cytoskeleton is dismantled to provide resources for the mitotic phase
Briefly what does the mitotic phase do? What 2 main phases are there?
The duplicates chromosomes (chromatids) are aligned, seperated, and moved into new, identical daughter cells
-2 main phases are karyokinesis and Cytokinesis
What are all the stages in order of karyokinesis?
Prophase, prometaphase, metaphase, anaphase, telophase and cytokinesis