Biology (LE) Review Guide

Topic 1:

Similarities and Differences Among Living Things

1. Characteristics of Life

   1. Living things are made up of cells

   2. They grow and develop

   3. Metabolism: all of the life activities

   4. Carry on ENZYME-CONTROLLED REACTIONS

   5. Homeostasis: keeps internal STABILITY

   6. Reproduce and pass on genes

2. Life Processes

   1. Nutrition: breaks down materials for transport

   2. Transport: moves materials around the organism

   3. Respiration: releases energy

   4. Synthesis combines smaller molecules TO MAKE more complex ones

   5. Excretion: removal of cellular wastes

   6. Regulation: control and coordination of activities

   7. Reproduction: to make more of the species

3. Chemical Composition

   1. Organic Compounds: contain both carbon and hydrogen

      1. Carbohydrates → sugars (glucose) and starches

      2. Lipids → fats

      3. proteins → made up of amino acids (enzymes and hormones)

      4. Nucleic acids → made up of nucleotides (DNA and RNA)

   2. Inorganic Compounds: Do not contain carbon and hydrogen

Organization of Living Things

1. Groups of Cells Work Together in Complex Organisms

   1. cells → tissues → organs → organ systems → organisms

2. Organelles

   1. Cytoplasm: holds all organelles, site of reactions, cyclosis

   2. Nucleus: controls all cell activities, holds DNA (chromosomes)

   3. Vacuole: storage site (small in animal cells, large in plant cells)

   4. Ribosome: site of protein synthesis

   5. Mitochondria: powerhouse of the cell, produce energy (ATP), cellular respiration

   6. Chloroplast: only in plant cells, site of photosynthesis

   7. Cell Wall: protects and supports plant cell

   8. Cell Membrane: regulates what enters and leaves the cell, selectively permeable

      1. Made up of proteins and lipids

      2. Contains receptors → cell communication

      3. Does not prevent harmful substances from entering the cell

Cell Transport

1. Passive Transport

   1. Passive Transport: no energy, substances move from HIGH TO LOW concentration

   2. Diffusion: movement of particles from high to low

   3. Osmosis: movement of water from high to low

      1. When placed in distilled water: water diffuses into cell

         1. Animal Cell: whole cell swells and bursts

         2. Plant Cell: inside will swell a bit but will not burst because of cell wall

      2. When placed in a salt diffusion: water diffuses out of cell

         1. Animal Cell: cell shrivels up

         2. Plant Cell: inside will shrivel up, not the whole cell

2. Active Transport

   1. Active Transport: uses energy, substances move from LOW TO HIGH concentration

Digestion

1. Large molecules are too big to pass through the cell membrane → must be BROKEN DOWN to enter cell

   1. Starch → simple sugars (glucose)

   2. Protein → amino acids

Recognizing Signals (Cell Communication)

1. Cells can communicate with each other using receptors (proteins) on cell membrane

   1. Receptors: receive chemical messages

      1. Chemical messages (hormones or neurotransmitters) must have the correct shape to bind with the receptor

Human Body Systems

1. Digestive System

   1. Breaks down molecules to make them small enough to pass through cell membrane and into cells

   2. One way tube

   3. Mouth → Esophagus → Stomach → Small Intestine → Large Intestine → Anus

   4. Mechanical Digestion: food broken down into smaller pieces (chewing)

   5. Chemical Digestion: broken down using enzymes

   6. Disorders: constipation, diarrhea, ulcers, gallstones, appendicitis

2. Respiratory System

   1. Gas exchange (oxygen and carbon dioxide) between the blood and the environment

   2. Nose → Trachea → Bronchi → Bronchioles → Alveoli (gas exchange)

   3. Disorders: asthma, bronchitis, emphysema, pneumonia

3. Circulatory System

   1. Transport materials (gases, nutrients, wastes, hormones, enzymes) throughout the body

   2. Heart, blood vessels (arteries, veins, capillaries), blood

   3. Disorders: angina pectoris, coronary thrombosis, anemia

4. Excretory System

   1. Removes cellular or metabolic wastes

   2. Kidneys: filters out blood, regulates concentration of substances in blood, makes urine

   3. Urinary System: ureters → urinary bladders → uretha

5. Nervous System

   1. Regulates all body processes

   2. Sends electrochemical impulses through neurons

   3. Brain, spinal cord, nerves

   4. Neurotransmitter: chemical released into synapse to transport impulse to next neuron

      1. Reflex Arc: receptor → sensory neurons → interneurons → motor neurons → effector

      2. Disorders: polio, cerebral palsy, meningitis, stroke

6. Endocrine System

   1. Regulates all body processes

   2. Made up of glands that produces hormones (travel through blood)

   3. Negative Feedback, Positive Feedback

   4. Disorders: goiter, diabetes, dwarfism, gigantism

7. Immune System

   1. Ability to resist diseases

   2. Involves WBC’s (engulf and destroy pathogens) and antibodies

How Systems Interact With Each Other

1. All Body Systems Interact to Maintain Homeostasis

   1. Nutrients from digestive system are transported to cells by circulatory system

   2. Reproductive system is regulated by endocrine system

   3. Excretory system filters out cellular wastes from blood in the circulatory System

2. If system fails → disrupts homeostasis (leads to a disorder)

Topic 2:

Homeostasis in Organisms

1. Photosynthesis

   1. Light energy is transferred to chemical energy (autotrophic nutrition)

   2. source of energy → sunlight

   3. Water + Carbon Dioxide + Sunlight → Glucose + Water + Oxygen

   4. occurs in chloroplasts of leaves

   5. needed in order for respiration to occur (to produce energy)

2. Cellular Respiration

   1. uses organic materials (glucose) to release energy (ATP)

   2. Aerobic: Glucose + Oxygen → Carbon Dioxide + Water + 36 ATP

   3. Occurs in Mitochondria

   4. Anaerobic: Does not use oxygen

      1. Yeast → produce alcohol, carbon dioxide, and 2 ATP

      2. Muscle Cells → produces lactic acid, 2ATP (Muscle Fatigue)

3. Enzymes

   1. Regulate rate of reaction

   2. Each have a specific shape → only bind to a specific substrate

      1. forms an enzyme-substrate complex

   3. Factors affect enzymes:

      1. pH: enzymes work best at certain pH

         1. acid: 1-6

         2. neutral: 7

         3. base: 8-14

      2. Substrate or enzyme concentration

      3. Temperature: when temperature reaches above 40 degrees → denaturation occurs

         1. Enzyme changes shape → cannot fit with substrate → reaction will not occur → enzyme activity decreases

Homeostasis and Feedback

1. Dynamic Equilibrium

   1. Homeostasis

   2. Negative Feedback: an increase in one substance causes a decrease in another

      1. Pancreas → when blood glucose level is too high, insulin is secreted, when blood glucose is too low glucagons are secreted

      2. Guard Cells → regulate gas exchange in leaves → close stomates when water is low

2. Disease

   1. Failure to main homeostasis

   2. Can be caused by pathogens, toxins, poor nutrition, organ malfunction

   3. Pathogen: anything that causes disease → virus, bacteria, fungi, parasites

   4. Cancers: genetic mutations in a cell that cause UNCONTROLLED CELL DIVISION (mitosis)

      1. Immune System

   5. detects invaders by pathogen’s antigens → proteins on surface

   6. white blood cells

      1. Engulf and destroy pathogens

      2. Produce antibodies that destroy pathogen

   7. Vaccines: dead or weakened pathogens injected into the body → stimulates body to produce

      1. antibodies → attach to antigens to help destroy pathogen

      2. memory cells → immune system remembers the pathogen (active immunity)

3. Disorders of Immune Systems

   1. AIDS: caused by HIV

      1. attacks the immune system → body unable to protect the body against pathogen

   2. Prevention: abstinence, protected sex (condoms), don’t share infected needles

   3. Organ Rejection: transplanted organ seen as invader and body attacks it

   4. Allergies: immune system reacts to a harmless substance as if it were dangerous

      1. pollen, food, insect bits, animals

      2. body produces histamines → cause symptoms of allergy (sneezing, runny nose, rash, swelling, etc..)

Topic 3:

Genetic Continuity

1. Heredity and Genes

   1. Heredity: passing of genetic information (DNA)

   2. DNA is made up of genes

   3. Thousands of genes on chromosomes

   4. Most traits are controlled by 2 genes/alleles

2. The Genetic Code

   1. DNA is a double helix shape

      1. made up of nucleotides

         1. Base pairs: A - T, C - G

   2. DNA Replication:

      1. DNA unzips (hydrogen bonds between bases break)

      2. Complimentary nucleotides attach to bases on the separate DNA strands

      3. Produce 2 new DNA molecules that are identical

3. Protein Synthesis

   1. Join amino acids to make a protein/polypeptide

   2. Occurs at ribosomes

   3. DNA controls the sequence of amino acids in protein

      1. DNA is used to a template to make mRNA (contains A, U, C, G)

      2. mRNA leaves the nucleus and goes to the ribosomes

4. Mutations

   1. Change in genetic material

   2. Types of mutations:

      1. Chromosome mutations: change in chromosome number or structure

         1. Nondisjunction: when tetrad does not separate properly during meiosis

            1. causes Down Syndrome → extra chromosome in pair 21 (Trisomy 21)

            2. detected by karyotype (knows what it looks like)

         2. Polyploidy: when the organism is 3n or 4n instead of 2n

      2. Gene mutation: change in DNA code

         1. a base could be added, deleted, or substituted→ changes the codon on mRNA produced → different protein produced → leads to a genetic disorder

         2. Sickle cell anemia: lack of an amino acid → changed shape of the hemoglobin on red blood cells → doesn’t function properly