Exam 5 Flashcards
What are the two types of reduction?
Asexual
Sexual
What is asexual reproduction also known as?
mitosis
what is sexual reproduction also known as?
meiosis
define asexual reproduction
offspring are identical to the original cell/organism
inheritance of all genes from one parent
define sexual reproduction
offspring are similar to parents but show variations in traits
inheritance from both parents
define gene
unit of hereditary info consisting of a specific nucleotide sequence of DNA
Define binary fission
dividing in half
in what cells does binary fission occur?
prokaryotic cells
in binary fission are cells identical or do they have variations?
they are identical daughter cellx
what are the steps of binary fission?
- the single cellular chromosome duplicates and copies and begins to separate
- Cell elongates and continues to separate
- the plasma membrane grows inward at the midpoint to divide the cells
What are eukaryotic chromosomes composed of?
Chromatin
What us chromatin made of?
DNA and proteins (histones)
In chromatin what is the job of the two parts?
DNA: contains genetic information which directs body development and maintenance
Proteins: Help with support and control of gene activity
Define Somatic Cells
All cells except sperm and eggs
How many chromosomes are in humans?
46
23 pairs
How many chromosomes does each somatic cell contain?
2: one from each parent (Homologous)
Define Homologous
for every pair, there is one form mom and one from dad
Define Diploid
A cell with two full sets of chromosomes
-Each pair of chromosomes in a diploid cell is considered to be a homologous chromosome set
Which parent determines the gender of a baby?
the 23rd male sperm
Define Cell Cycle
an ordered sequence of events for cell division of somatic cells
What are the two phases of the cell cycle?
Interphase and Mitotic Phase
What percent of the cell cycle are the two parts?
Interphase: 90%
Mitotic phase: 10%
What happens during Interphase?
period of growth and preparation for cell division (duplication phase)
What does G1 mean?
Growth, increase in cytoplasm
What does S mean?
Duplication of chromosomes
What does G2 mean?
Growth, preparation for division
What happens in G1?
The first “GAP” where there is a growth of the cytoplasm
What happens in S?
DNA is replicated, and the two copies of the chromosome and remain attached at the centromere
Define Chromatids
each of the two threadlike strands into which a chromosome divides longitudinally during cell division
What happens in G2?
The “second gap”. The period after DNA is synthesized and before mitosis begins
What are the phases of cell division?
Mitosis and Cytokinesis
What happens in mitosis?
Division of the nucleus
What happens in cytokinesis?
Division of the cytoplasm
What are the four phases of mitosis?
Prophase
Metaphase
Anaphase
Telophase
What happens in Prophase?
- Chromatin condenses and forms chromosomes as DNA wraps around histones
- Nuclear membrane begins to break down
- Mitotic spindle forms
What happens in Metaphase?
Chromosomes attach to mitotic spindles and form a line at the center of the cell
What happens in Anaphase?
Sister chromatids of each chromosome begin to separate, splitting at the centromere.
-(now separate and considered chromosomes)
What happens in Telophase?
Nuclear envelope forms around each group of chromosomes at each pole
-mitotic spindle disassembles
(end of splitting nucleus)
What happens in Cytokinesis?
Cytoplasm divided into separate cells
Define cleavage furrow
forms from a contracting ring of microfilaments
What happens with cytokinesis in animal cells?
The cleavage furrow deepens to separate the contents into two cells
What happens with cytokinesis in plant cells?
A cell plate forms in the middle from vesicles containing cell wall material dividing the contents into two cells
