Mitosis & Meiosis (Chapter 3) Flashcards
Chromosome Theory of Inheritance
-Describes how the transmission of chromosomes account for mendelian patterns of inheritance.
-Established how chromosomes carry and transmit genetic determinants of traits
The three lines of scientific inquiry unfolded through the chromosome theory of inheritance:
- Analysis of the transmission of traits from parents to offspring
- Inquiry into the basis of heredity
- Microscopic examination of the processes of mitosis, meiosis and fertilization.
The chromosome theory of inheritance is based on the following fundamental principles:
- Chromosomes contain genetic material
- Chromosomes are replicated and passed from parent to offspring
- The nuclei of most eukaryotic cells contain chromosomes that are found in homologous pairs, called diploids
- During the formation of gametes, different types of chromosomes segregate independently.
- Each parent contributes one set of chromosomes to its offspring, each set being a full complement of genes.
Chromsomes are:
Structures within living cells that contain the genetic material, containing genes
Chromosomes are composed of:
-DNA, the genetic material
-Proteins, providing the organized structure of the chromosome
(DNA-protein complex is called chromatin)
Chromosomes in Bacterial Cell:
-Contain a single circular chromosome, found in the nucleoid with the cytoplasm/no nucleus
- Cytoplasm enclosed by a plasma membrane, regulating nutrient uptake and waster excretion
-The rigid cell wall outside the membrane protect the cell from breakage.
Chromsomes in Eukaryotic Cells:
-Nucleus contains the genetic material, having multiple chromosomes and 2 membranes
- Mitochondrion is where Respiration/ATP Synthesis occur, containing genetic material/DNA
-Centriole responsible for organization of spindle fibers
-Protein Synthesis occur in the RER(Rough endoplasmic reticulum)
Ploidy:
Refers to the number of copies each chromosome has in a cell:
-Haploid(n)-one copy
-Diploid(2n)-two copies
-Triploid(3n)- three copies
Humans have a total of 46 chromosomes(23 chromosomes per set)
Biparental inheritance
For each chromosome pair, one chromosome comes from each parent.
These chromosomes are homologues/homologous chromosomes
Cytogenetics:
-Microscopic examination of chromosome, allowing detection of abnormal chromosome structure or number, distinguishes between two-closely related species.
Animal Cells are of two types:
-Somatic cells(Diploid)
Body cells, not including gametes
-Germ cells(Haploid)
Gametes-sperm and egg cells.
Karyotype
-An organized representation of chromosomes within a cell
Homologous Chromosomes
Two chromosomes in a homologous pair(homologs)
-Evolutionarily related
-Nearly identical in size
-Same banding pattern and centromere location
-Have the same genes, but it is not guaranteed they have the same alleles.
Sex chromosomes (X and Y) are homologous meaning:
-Sex chromosomes behave as homologs in meiosis
-Related but there are drastic changes that have accumulated over time,
-Differ in size and genetic composition
-Short regions of homology
-Inherited as a pair
Importance of Cell Division:
–Purpose of cell devision is asexual reproduction, the same process some unicellular organisms go through to produce new individuals.
–Cell Division allows for multicellularity, we are all derived from a single cell that has undergone repeated cell division.
Prokaryotes Reproduce Asexually by Binary Fission. Explain
-DNA in the cell is replicated
-DNA attaches to the membrane at the origin of replication (oriC)
-As a new membrane is synthesized, the replicated nucleoids/bacterial chromosomes grow apart, creating two groups of nuceloids in the cell
- An FtsZ protein recruits proteins to form a new cell wall between new membranes.
-A New cell membrane and wall are laid down in the middle of the cell at the Septum, then the cell segregates into daughter cells(2 daughter cells produced)
Eukaryotic Cells progress through the cell cycle
-Interphase
