Science

Lesson 1: Biology

Biology

- deals with the study of living things.

Bio - life

Logy - study

Structure and functions of a digestive system:

1. Ingestion

-the process of taking food, drink, or another substance into the body by swallowing or absorbing it.

2. Digestion

-the process of mechanically and enzymatically breaking down food into substances for absorption into the bloodstream.

3. Excretion

-the process of removing wastes and excess water from the body.

Mechanical digestion

-physically breaking down food substances into smaller particles by tearing, grinding, chewing.

Chemical digestion

-the process where complex molecules like proteins, fats, and carbohydrates are broken down into smaller pieces that your body can use.

Mouth

-the teeth mechanically break down food into smaller pieces.

Esophagus

-20cm long 

-creates mucus

-connects pharynx into stomach

-moves down food from the throat to the stomach

Peristalsis - swallowing

Anti-peristalsis - vomiting

Stomach

-break down proteins and lipids

-has gastric juices

Small intestine

-7 meters long

-finger like projections called villi

-absorbs vitamins, mineral, water, liquid

Large intestine

-1.5 meters long 

-accept what the small intestine doesn’t absorb.

Rectum

-short term storage

Parts of a Small Intestine:

Duodenum, ileum, jejunum

Accessory organs

-include salivary glands, liver, and pancreas.

6 salivary glands:

- 2 submaxillary

- 2 parotid glands

- 2 sublingual glands

Liver

-yellow green liquid called bile which is stored in the gallbladder.

Gallbladder

-pear-shaped organ under the liver

Pancreas (lapay)

-produce digestive enzymes to digest fats

Disorders and diseases of digestive system

Disorders

-disturbance with the functions

• Diarrhea

-loose bowel movement

-accompanied with vomiting

• Constipation

-feces that are hard to pass

• Irritable bowel syndrome (IBS)

-either diarrhea or constipation

-caused by stress

• Obesity

-fat in the body

-when the body takes in more fat than it needs.

• Lactose intolerance

-inability to eat/consume sugar

Diseases

-affects the structure or function of all or part of an organism.

• Gastroesophageal reflux disease (GRD)

-the acid

-burning sensation

-esophagus is damaged

• Peptic ulcer

-painful lesion of the stomach and small intestine

• Gastritis

-causes inflammation of the lining of stomach

• Colon cancer

-uncontrolled growth of cells in the intestine

Lesson 2: Mitosis and Meiosis

Main parts of the cell

1. Cell membrane - separates the interior of the cell from the outside environment.

2. Cytoplasm - the gelatinous liquid that fills the inside of a cell.

3. Nucleus - the structure in a cell that contains the chromosomes. 

Centrioles - structure of the cell that is responsible for cell division. 

Importance of meiosis

1. Produce haploid cells

2. Replace cells

Cell division

- mitosis

- meiosis

Mitosis

- body cells

- 46 chromosome (23 each from father and mother)

- diploid

- 2N

- 2 daughter cells

Meiosis

- sex cells

- 4 daughter cells

Cell cycle

- interphase and mitotic phases

Interphase

- the phase of the cell cycle in which a typical cell spends most of its life.

Some cells undergo the cell cycle ones

Go phase

- the phase of the cell cycle in which a typical cell spends most of its life.

Pro phase

- chromosomes condense

- the nuclear envelope break down

Metaphase

- are pulled at the center of the cell

- line up along the “metaphase plate”

Anaphase

- centrosomes divide

Telophase

- the effects of prophase and prometaphase are reversed.

- final stage

Cytokinesis

- pitching of plasma membrane

Meiosis

-important in reproduction

Homologous pair

- only one pair differ sex chromosomes x or y

Xx - girl

Xy - boy

Xxy or xyx - some characteristics may be for a girl or boy. 

Synapsis

- pairing of homologous chromosomes farming tetrad

Crossing over

- chromatids or tetrad exchange parts

Prophase 1

- Prophase I is the defining substage of meiosis, in which specific events take place to ensure accurate segregation of homologous chromosomes and thus, reduction of the genetic content in daughter cells

Metaphase 1

- tetrads or homologous chromosomes pulled.

Anaphase

- homologous pulled to opposite poles

Telophase 1

- daughter nuclei formed

Meiosis 2

- the sister chromatids separate, making haploid cells with non-duplicated chromosomes.

Prophase 2

-spindle fibers form again

Metaphase 2

-sister chromatids move to the center

Anaphase 2

- separation of the sister chromatids

Telophase 2

-  The chromosomes gather at the 2 poles of the cell and the cell divides via cytokinesis forming 2 daughter cells from each of the two cells from meiosis I.