BIOLOGY

3 postulates of cell theory

3 postulates of cell theory

1. all organisms are made of cells

2. cells are the basic units of life

3. new cells arise from pre-existing ones.

4 features that prokaryotes and eukaryotes share

ribosomes, mitochondrian cytoplasm cell membrane

cell membrane

thin, flexible barrier around a cell; regulates what enters and leaves the cell

Cytoplasm

A jellylike fluid inside the cell in which the organelles are suspended

Mitochondria

Powerhouse of the cell

Ribosomes

Makes proteins

Endoplasmic Reticulum

A cell structure that forms a maze of passageways in which proteins and other materials are carried from one part of the cell to another.

vesicles

small membrane sacs that specialize in moving products into, out of, and within a cell

Lysomes

Uses chemicals to break down food and worn out cell parts

Golgi body

A structure in a cell that receives proteins and other newly formed materials from the endoplasmic reticulum, packages them, and distributes them to other parts of the cell.

Nucleus

Control center of the cell

Vacuole

A sac inside a cell that acts as a storage area

Cytoskeleton

A network of long protein strands in the cytosol that helps support the cell

cell wall

strong, supporting layer around the cell membrane in some cells

Chloroplast

Site of photosynthesis

3 reasons why cells divide

growth, repair, reproduction

Stages of Interphase

G1, S, G2

G1 phase

Cell growth

S phase

DNA replication

G2 phase

stage of interphase in which cell duplicates its cytosol and organelles

mitosis

cell division in which the nucleus divides into nuclei containing the same number of chromosomes

cytokinesis

division of the cytoplasm to form two separate daughter cells

Stages of Mitosis

interphase, prophase, metaphase, anaphase, telophase

interphase

period of the cell cycle between cell divisions

Prophase

first and longest phase of mitosis, during which the chromosomes become visible and the centrioles separate and take up positions on the opposite sides of the nucleus

metaphase

Chromosomes line up in the middle of the cell

Anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

Telophase

the final phase of cell division, between anaphase and interphase, in which the chromatids or chromosomes move to opposite ends of the cell and two nuclei are formed.

Chromosomes

threadlike structures made of DNA molecules that contain the genes

chromatin

Clusters of DNA, RNA, and proteins in the nucleus of a cell

sister chromatids

joined copies of the original chromosome

Centromere

Area where the chromatids of a chromosome are attached

What causes cancer?

defects in genes that regulate cell growth and division

Malignant tumour cells

often known as cancers, they invade neighbouring tissues and spread to different parts of the body in the blood where they form secondary tumours

benign tumor

a mass of abnormal cells that remains at the site of origin

5 Carcinogens

1. Ultraviolet Rays

2. Tobacco

3. Alcohol

4. Wood dust

5. Gamma rays

3 factors that affect risk of cancer

genetics, exposure to carcinogens age

Why is smoking harmful?

Cigarette smoke contain poisonous chemicals that harm the lungs and other parts of the body. As smoke particles get in the lungs and cool, they form a sticky tar that keeps the cilia from working properly. The smoke can also keep the alveoli from working properly.

5 ways cancer is diagnosed

breast self examination self testicular examination PSA test for prostate cancer blood test for colon cancer pap test for cervical cancer

3 ways cancer is treated

surgery, chemotherapy, radiation

stem cells

undifferentiated cells

cell differentiation

the process by which cells become different types of cells

4 types of specialized cells

epithelial tissue connective tissue muscle tissue nerve tissue

categories of nutrients body requires

carbohydrates proteins lipids vitamins minerals water

mechanical digestion

Physical breakdown of large pieces of food into smaller pieces

chemical digestion

Process by which enzymes break down food into small molecules that the body can use

Pathway of food through digestive system

mouth, pharynx, esophagus, stomach, small intestine, large intestine, rectum

3 Accesory Organs

liver, gallbladder, pancreas

vein

A blood vessel that carries blood back to the heart; thin elastic wall

artery

carries blood away from the heart; thick elastic wall

capillary

smallest blood vessel; brings nutrients and oxygen to the tissues and absorbs carbon dioxide and waste products; small and thin

4 components of blood

plasma, red blood cells, white blood cells, platelets

Process of gas exchange in the lungs

During gas exchange oxygen moves from the lungs to the bloodstream. At the same time carbon dioxide passes from the blood to the lungs. This happens in the lungs between the alveoli and a network of tiny blood vessels called capillaries, which are located in the walls of the alveoli.

organs involved in inhaling

ribs pulled up and out diaphragm contracts and moves down increase in lung volume pressure in lung decreases

organs involved in exhaling

ribcage falls decrease in lung volume diaphgram relaxes and moves up pressure in lung increases

Pathway of air into the lungs

Nose/Mouth Pharynx Epiglottis Larynx Trachea Bronchi Bronchioles Alveoli