Honors Bio Final

G1

Cells growing

S

Synthesis (replicating DNA)

G2

More growing and double checking DNA replication

What happens in interphase?

• growth

• DNA replication

• cell functions

G1

Cells growing

S

Synthesis (replicating DNA)

G2

More growing and double checking DNA replication

What happens in interphase?

• growth
• DNA replication
• cell functions

How long does a cell live?

Varies, different types have different life spans

What is G0 and why is it important?

A gap year. A state in which a mature cell exists in the normal interphase process and just maintains

Why does a cell divide?

To reproduce, to grow, or to replace dead or dying cells

Chromosome

Condensed DNA

Chromatin

The material in which chromosomes are made of (DNA and protein)

What needs to happen before mitosis can begin

DNA replication and making sure a cell is large enough

(Mitosis) Prophase

• chromosomes condense
• mitotic spindle forms from centrioles
• the nucleus dissolves
• spindle fibers attach to centromeres

Most humans have how many chromosomes?

46

Why do unicellular and multicellular organisms need to do mitosis?

• Unicellular: needs to reproduce
• Multicellular: needs to replace dead/dying cells

Why do you have two types of each chromosome?

So you can get one from each parent

How does cellular reproduction differ in eukaryotic and prokaryotic cells?

E: do mitosis
P: do binary fission

What percent of the cell cycle is each stage?

Mitosis: 10%
Interphase: 90%

Which stage does a cell spend the majority of its life in?

interphase

What are the 2 stages of a cell's life?

Interphase and Mitosis

What are the 4 stages of mitosis?

Prophase, Metaphase, Anaphase, Telophase (PMAT)

Mitosis

The division of one cell into two genetically identical cells (clones)

Centromere

Area where the chromatids of a chromosome are attached. Also where the spindle fibers attach

Chromatid

Each half of the chromosome

Centrioles

creates spindle fibers

Cytokinesis

division of the cytoplasm

Spindle fibers

Divide genetic material in the cell

(Mitosis) Metaphase

Cells chromosomes condense, chromosomes align along the middle, and the nucleus divides

(Mitosis) Anaphase

The sister chromatids break apart, and the chromosomes begin moving to opposite ends of the cell

(Mitosis) Telophase

The chromosomes arrive at the cell poles, the mitotic spindle dissolves, and nucleus comes back together.

What happens to the newly created "daughter cells" after mitosis?

After mitosis, cytokinesis divides the parent cell into 2 complete daughter cells

Where are the chromosomes in a cell found?

nucleus

How is cytokinesis different between plant and animal cells?

The animal cell pinches apart while the plant cell divides

What is the goal of mitosis?

produce two identical daughter cells

What is the product of mitosis?

2 identical daughter cells

Karyotype

a visual representation of the genome

Genome

all of an organism's genetic material

Gene

basic unit of heredity passed from the parent to the child

Haploid

refers to a cell that contains a single set of genes

Diploid

containing two complete sets of chromosomes, one from each parent

Fertilization

Process in sexual reproduction in which male and female reproductive cells join to form a new cell

Homologous Pair

chromosomes in which one set comes from the male parent and one from the female parent, they are also similar in size and contain the same gene type

Why are homologous chromosomes important?

They are important for ensuring proper chromosome segregation during meiosis and creating genetic diversity in offspring

Tetrad

structure containing 4 chromatids that forms during meiosis

Somatic

any cell of a living organism other than the reproductive cells

Gamete

reproductive cell that has one set (half the number or chromosomes)

Zygote

the fertilized egg cell (it is diploid)

Synapsis (crossing over)

the exchanging of genetic material between chromosomes during prophase 1

Why is crossing over necessary

generates new combinations of alleles and contributes to genetic diversity

Law of segregation

When alleles segregate randomly into gametes

law of independent assortment

The alleles of two or more different genes get sorted into gametes independent of one another

n

number of chromosomes in a haploid cell

Germ cells

diploid cells that can use meiosis to make gametes

What is the end goal of meiosis?

to create 4 genetically different haploid cells

(Meiosis) Prophase 1

• Spindle fibers form from centrioles
• Nucleus dissolves
• Homologous pairs line up forming tetrads and crossover identical genes

(Meiosis) Metaphase 1

• Homologous pairs line up tetrads on either side of the metaphase plate
• They arrange themselves independently of the other pairs

(Meiosis) Anaphase 1

• Homologous pairs separate as chromosomes are pulled towards the centrioles

(Meiosis) Telophase 1

• Two cells are created via cytokinesis
• Each cell is haploid (n) and has 1 of each original homologous pair 23 in total

(Meiosis) Prophase 2

• Spindle reforms
• Nucleus dissolves
• Cells are considered haploid (crossing over DOES NOT happen)

(Meiosis) Metaphase 2

• Chromosomes line up single file on the metaphase plate

(Meiosis) Anaphase 2

• Chromosomes are split at their centromere and chromatids are moved towards the poles of the cell

(Meiosis) Telophase 2

• Nucleus reforms and cells divide from 2 into 4 via cytokinesis cells are still considered haploid
• After T2 the cells are processed into gametes

Gametes (step)

4 genetically unique haploid (n), gamete cells are created

Meiosis in females makes…

egg cells

Meiosis in males makes…

sperm cells

What happens before meiosis

interphase

What must happen before meiosis?

DNA must duplicate (makes 92 chromatids)

Recombinant chromosomes

result of crossing over

Somatic cells are

diploids

Gametes are

haploids

Heredity

Passing of traits from parents to offspring

Inheritable trait

traits that are passed on from the parent generation to any offspring they have by genes

Trait

a specific characteristic (eye color, height, etc…)

Hybrid

the offspring of crosses between parents with different traits

Genes (heredity)

factors passed from parent to offspring

Alleles

Different forms of a gene

Principle of Dominance

states that some alleles are dominant and others are recessive

Segregation

Separation of alleles during gamete formation

Gametes

reproductive cells

Probability

percent chance

Homozygous

an organism that has two identical alleles for a trait (TT or tt)

Heterozygous

organisms that have two different alleles for the same gene (Tt)

Phenotype

physical characteristics of an organism

Genotype

genetic makeup of an organism (letters)

Job of a punnet square

helps predict probability

Independent assortment

genes for different traits can segregate independently during the formation of gametes

Monohybrid cross

only looking at one trait

Dihybrid cross

looking at TWO traits at the same time

How many squares will the punnett square for a dihybrid cross have?

16

How many squares will the punnett square for a monohybrid cross have?

4

How many of your 46 chromosomes are your sex chromosomes?

2

Female chromosomes

XX

Male chromosomes

XY

Sex-linked (aka X-linked)

refers to the pattern of inheriting traits or diseases linked to genes on the X chromosome

Autosomal dominant

a person inherits a trait from one parent

Autosomal recessive

inheritance means a person inherits a trait from both parents

What does automsal mean?

anything but sex cells

Pedigree

a sort of "family tree", it can show information about traits across generations