Biology Chapter 8 Quest Section 1 and 2
The cell cycle is controlled at three checkpoints. Describe each of them, including when they occur in the cell cycle:
1. At the G1 checkpont it makes sure the cell is at a suitable size. 2. DNA synthesis G2 Checkpont. If correct protiens enter mitosis 3. Mitosis check pint gives the clear for the cell to divide.
How many human chromosomes are in a haploid cell?
23
How many human chromosomes are in a diploid cell?
46
Telophase
After the chromosomes reach opposite ends of the cell, the spindle fibers disassemble, and the chromosomes return to a less tightly coiled chromatin state
Autosomes
All of the other chromosomes in an organism
Explain the difference between autosomes and sex chromosomes:
Autosomes are chromosomes that determine traits of the organism. Sex Chromosomes determine the sex of the organisms.
What is the purpose of the G0 phase?
Cell Cycle stops
Explain the difference between a chromosome and chromatin:
Chromatin is the DNA before it coils. Chromosomes are thr coiled DNA
Histones
DNA in eukaryotic cells wraps tightly around proteins
Chromatid
Each half of the chromosome
Describe the three stages of interphase. What happens in each?
G1: The first growth stage S: DNA replicates itself G2: Last period of growth and prep.
Explain the difference between haploid and diploid:
Haloid: cell contains both sets of chromosomes. Diploid: cell contains one set of chromosomes.
The proteins involved in making chromosomes are called:
Histones
Cell Plate
In plant cells, vesicles from the Golgi apparatus join together at the midline of the dividing cell
How does cytokinesis differ in plant cells and animal cells?
In plants, a new cell wall forms, vesicles line up and form a cell plate. In animals, the cleavage furrow forms.
3 Stages of the Cell Cycle are:
Interphase, Mitosis, Cytokinesis
Why would eukaryotic organisms need mitosis?
Mitosis results in new cells with genetic material that is identical to the genetic material of the original cell.
Explain at least 3 differences between a prokaryotic chromosome and a eukaryotic chromosome:
Shape: Prokaryotes:Un-coiled- circular in shape Eukaryotes: Coiled- More complex, coiled up in a rod shape. Number: Prokaryotes: Only 1 Chromosome Eukaryotes: More than one chromosome. Location: Prokaryotes: Chromosome attached to the cell membrane Eukaryotes: Chromosomes found in nucleus
Explain what could happen if the process of mitosis was not regulated correctly:
The cell could mutate causing rapid cell reproduction or cancer.
Describe the structure of a duplicated chromosome. Include the terms centromere and chromatid:
The centromere is the place at the center to keep the chromatids together. The chromatids are the things that have DNA.
Chromatin
The less tightly coiled DNA-protein complex
Centromere
The two chromatids of a chromosome are attached at a point
Homologous Chromosomes
The two copies of each autosome
Karyotype
a photomicrograph of the chromosomes in a normal dividing cell found in a human.
Sex chromosomes
chromosomes that determine the sex of an organism, and they may also carry genes for other characteristics.
Prophase
first phase of mitosis, begins with the shortening and tight coiling of DNA into rod-shaped chromosomes that can be seen with a light microscope.
Gametes
haploid reproductive cells.
Spindle Fibers
made of microtubules radiate from the centrosomes in preparation for metaphase.
Meiosis
occurs in the formation of gametes
Chromosomes
rod-shaped structures made of DNA and proteins
Anaphase
the chromatids of each chromosome separate at the centromere and slowly move, centromere first, toward opposite poles of the dividing cell
Explain binary fission:
the division of prokaryotic cell into two offspring cells.
Asexual reproduction
the production of offspring from one parent.
Metaphase
the second phase of mitosis. During metaphase, chromosomes are easier to identify by using a microscope than during other phases
