BI 253 Chapters 12-13
Card Set Information
BI 253 Chapters 12-13
Ch 12-13 11-11-12
Which type of reproduction provides genetic diversity & why?
Sexual b/c genetic material is shuffled
Reproduction based on mitotic division of the nucleus is ___ or ___.
Asexual or cloning
____ reproduction provides genetic material fr both parents.
Variation in asexual reproduction is due to ____ not the parents.
In asexual reproduction offspring ____ identical to parents where as in sexual reproduction offspring ___ identical to parents
Mitosis is the division of ____ cells where as Meiosis is the division of ___ or ___ cells.
Gametes or Sex
Mitosis creates ____ copies where as Meiosis creates ___ copies.
What are the 5 steps in mitosis?
In mitosis, what is the relationship between amt of genetic material @ beginning & end?
There is the same amt at beginning & end
The process of meiosis ends w/ ____ the genetic material it started with.
In meiosis, the nucleus divides ____ but the DNA replicated ____.
How many daughter cells are formed in meiosis?
What are 3 functions of Meiosis?
Reduce chromosome fr 2n → n
Ensure each gamete gets a set of chromosomes
Promote genetic diversity
Each of a pr of DNA molecules after DNA replication is called a ____.
What structure joins 2 chromatids together?
The protein/DNA complex that makes up chromosomes is called ____.
What term describes DNA complexed w/specific proteins that are responsible for storage & transmission of genetic material?
How do chromatids, chromatin & centromeres all come together?
2 chromatids, made of chromatin, are held together at a centromere
Proteins that DNA wraps around during interphase are called ___?
What is a nucleosome & what does it look like?
DNA wrapped around a histone
Looks like beads on a string
Nucleosomes are made up of ___ histone molecules w/ ___ base prs of DNA utilizing histone H1 to what?
Clamp DNA to the core
What structure separates daughter cells during cell division?
What are 2 types of microtubules that make up the mitotic spindle?
What do polar microtubules do in the mitotic spindle?
Form a frame work that overlaps & interacts w/both sides
What do kinetochore microtubules attach to and where?
Kinetochores on chromosomes
Regions where microtubules are formed are called what?
Centrosome (formed at home)
Each centrosome produces ___ ___.
Cylindrical structures that are composed of 9 triplet microtubules & form mitotic spindle are called ___.
Centrioles (plays a role)
The specialized region of the chromosome to which spindle fibers attach during cell division are called ____.
Centromere (attaches here)
Polar & kinetochore microtubules are formed in the ____.
Each centrism contains a pr of ___.
A chart that organizes chromosomes based on size, number & shape is called a ____.
What are 4 steps to create a karyotype?
Collect cell in metaphase
Pierce nucleus so chromosomes spill out
Separate them according to characteristics & organize on chart
What is the primary use for a karyotype?
Show Chromosomal abnormalities that cause genetic problems
What does a haploid describe & how is it denoted?
# of chromosomes in a Gamete cell
Denoted by "n"
When 2 haploid cells (egg & sperm) fuse in fertilization, a ___ is created that is a ___ (2n).
The number of chromosomes in a somatic cell is denoted ___ & is ___.
A pr of chromosomes where members share same genes & are similar but not identical are called ____ ____.
A ____ is one of a pr of chromosomes.
Egg & sperm are both ___ cells until fertilization then they become ____.
Prokaryotic cells divide by a process of ____ ____.
Binary Fission is a form of ____ reproduction.
Asexual reproduction & binary fission ALWAYS create daughter cells that are ____ to parents.
What are the steps in binary fission?
Cells grow in size
When a cells divides much like a drawstring bag when it closes it is called ____.
What are the 2 reproductive signals for binary fission?
Environmental conds just right
Proper nutrient concetrations
What is the origin of replication or where replication begins called?
The terminus of replication or where replication ends is called what?
What are the 2 primary phases of the cell cycle?
What are the 3 subphases of the interphase of the cell cycle?
Gap 1 (G1)
Gap 2 (G2)
When does the G1 phase of cell cycle occur?
Aft mitosis b/f synthesis
When some cells leave the G1 phase they go to a resting phase called ___.
At what point does a cell commit to dividing?
G1 → S transition
During the S phase of the cell cycle what happens?
DNA is synthesized or replicated
What 2 things do cells do during the G2 phase of cell cycle?
Prepares for mitosis
Makes microtubules for mitotic spindle
What do cyclins and Cyclin Dependent Kinases (CdK's) do?
Trigger phase to phase transitions in the cell cycle
What are cyclins & CdKs made up of?
Specialized proteins & enzymes
A ____ always present in a cell but active site not open until it binds with a ____.
Cyclin Dependent Kinase
Cyclins are made when?
At certain points in cell cycle depends on which 1 they are
When a cyclin & Cdk bind, exposing Cdk's active site, what events happen next?
Protein substrate & ATP bind to active site
Phosphorylated protein released to reg cell cycle
ADP also released
Cyclin D - Cdk 4 & cyclin E - Cdk 2 bind during ___ phase & accomplish what?
Phosphorylate Rb to move cell past restriction pt R
Cyclin A - Cdk 2 act during ___ phase & to stimulate ____ ____?
Stimulate DNA replication
Cyclin B - Cdk 1 act during the ___ → ___ boundary to initiate ____.
G2 → M
When speaking of gender chromosomes 2 X's = ____ & 1X & 1Y = ____.
What chromosomal abnormality occurs when either homologous chromosomes fail to separate during anaphase I or sis chromatids fail to separate during anaphase II?
A form of non disjunction where there are too many or not enough chromosomes is called ___.
What is the name given to a condition where there are whole extra sets of chromosomes?
____ occurs when part of 1 chromosome breaks off & attaches to another.