Biology Exam 2

What is a conjoined twin?

Identical twins whose bodies are physically attached at some location

Describe cell theory

The realization that all living organisms are made of cells; it was first proposed in 1839 by Matthias Schleiden and Theodor Schwann

Prokaryotes

no nucleus, no membrane-bound organelles

Eukaryotes

do have nucleus, membrane-bound organelles

Similarities between Prokaryotes and Eukaryotes

Cell membrane, genetic material, cytoplasm, ribosomes

What is the role of the cell membrane?

It regulates what enters and leaves the cell. The cell membrane also maintains the environment inside the cell — essential for the many thousands of chemical reactions that occur in cells

What is the function of the nucleus?

Contains genetic material

What is the function of the mitochondria?

Creates ATP (energy)

Describe the theory of endosymbiosis

Eukaryotes evolved from Prokaryotes. Bacterias being engulfed by Prokaryotes; they weren’t digested and they worked together in symbiosis

Chloroplast

Bacteria that can use sunlight energy to produce their own food

Mitochondria

Bacteria that can use oxygen to make ATP

What are the components of the endomembrane system?

Endoplasmic reticulum (ER), rough endoplasmic reticulum (RER), ribosomes, golgi apparatus, and lysosomes

Nucleus Components

Membrane & DNA

Nucleus Function

contains genetic material

Mitochondrion Components

Membrane & DNA

Mitochondrion Function

Creates ATP

Mitochondrion: Interactions with other organelles/cell features

all organelles

Rough Endoplasmic Reticulum Components

Membrane & ribosomes

Rough Endoplasmic Reticulum Functions

Creates proteins

Rough Endoplasmic Reticulum: Interactions with other organelles/cell features

Ribosomes & Golgi apparatus

Smooth endoplasmic reticulum Components

Membrane

Smooth endoplasmic reticulum Functions

Creates lipids and detoxes

Golgi apparatus Components

Membrane & enzymes

Golgi apparatus Function

Modifies proteins

Golgi apparatus: Interactions with other organelles/cell features

RER, vesicles

Vesicle Components

Membrane

Vesicle Functions

Trafficks proteins

Vesicle: Interactions with other organelles/cell features

RER, Golgi

Lysosome Components

Membrane & hydrolytic enzymes

Lysosome Functions

Digests DD/damaged organelles & macromolecules

Lysosome: Interactions with other organelles/cell features

Damaged/old organelles

Ribosome Functions

Creates proteins

Ribosome: Interactions with other organelles/cell features

RER

Cytoplasm/Cytosol Functions

Contains organelles, cell features

Cytoplasm/Cytosol: Interactions with other organelles/cell features

All organelles, cell features

Cytoskeleton Functions

Supports cell membrane, allows cell movement

Cytoskeleton: Interactions with other organelles/cell features

Cell membrane

Cell Membrane Functions

Protects cell, regulates what enters/leaves

Cell Membrane: Interactions with other organelles/cell features

Cytoskeleton

Mitosis Function

make somatic cells

Meiosis Function

Make gametes

Mitosis Steps/Phases of

PMAT

Meiosis Steps/Phases of

PMAT I and PMAT II

Mitosis occurs in what cells?

Somatic cells

Meiosis occurs in what cells?

Gametes

Is Mitosis genetically identical or different?

Identical

Is Meiosis genetically identical or different?

Different

Mitosis: Number of Divisions

1

Meiosis: Number of Divisions

2

Mitosis: Number of Cells Produced

2

Meiosis: Number of Cells Produced

4

Mitosis: Chromosome number (at end)

46

Meiosis: Chromosome number (at end)

23

Does crossing over occur in Mitosis?

No

Does crossing over occur in Meiosis?

Yes

Does Mitosis produce haploid or diploid cells?

Diploid

Does Meiosis produce haploid or diploid cells?

Haploid

Does Mitosis occur before or after fertilization?

After

Does Meiosis occur before or after fertilization?

Before

What is a homologue?

Pairs of Chromosomes

Compare testes and ovaries

Testes are in males and produce sperm while ovaries are in females and produce eggs.

Prophase I

CROSSING OVER OCCURS

Metaphase I

INDEPENDENT ASSORTMENT - Line up on metaphase plate

Anaphase I

Pulled a part

Telophase

Cytokinesis

*Each daughter cell is haploid

Prophase II

Metaphase II

*Single File Line

Anaphase II

*Pulled to poles

Telophase II

Cytopkinesis

*End result of meiosis is four haploid daughter cells

3 events that create genetic variability

Crossing over (Prophase)

Independent assortment (Metaphase)

Random fertilization