Cell Structure and Function

• Cells and organization

Animal Cell

• An animal cell contains a cell membrane, nucleus, mitochondria, and cytoplasm

Plant Cell

• A plant cell contains a nucleus, cell wall, cell membrane, cytoplasm, chloroplast and vacuole.

Functions of organelles

• Chloroplasts contain chlorophyll, which absorbs light for photosynthesis
• The nucleus contains genetic information that codes for the production of proteins
• Mitochondria are the site of aerobic respiration
• Cell wall provides structure to the cell
• Vacuole stores cell sap
• Cell membrane controls what enters and leaves the cell
• Cytoplasm is a jelly-like substance where most chemical reactions take place

Onion Skin Cell

• Onion skin cells lack chloroplasts because there is no light for photosynthesis

Microscope Slide Preparation (Onion Cells)

• Take a thin piece of onion skin and place it on a slide
• Add a drop of iodine solution
• Place a coverslip on top
• Place the slide on the microscope stage and focus

Stains

• Stains are used for highlighting certain organelles

• Methylene blue is commonly used for animal cells

• Iodine solution is commonly used for plant cells

• Amoeba and Euglena Adaptations

Amoeba

• Amoebas move and feed using pseudopods.
• Pseudopods extend for movement and surround the prey for digestion.

Euglena

• Euglena movement is aided by the flagellum
• Euglena feeds using chloroplasts for photosynthesis

Diffusion

• Diffusion is the movement of particles from an area of higher concentration to an area of lower concentration.
• Only fluids can diffuse because their particles can move around each other.
• Oxygen and water (inside the cell) are substances expected to diffuse into a cell, while water and carbon dioxide are expected to diffuse out of a cell.

Definitions

• Tissue: Cells of the same type joined together (e.g., muscle)
• Organ: Tissues of different types joined together (e.g., heart, lungs, roots, leaves)
• Organ system: A number of organs working together (e.g., digestive, reproductive, shoots, roots)
• Organism: Made of cells, can carry out all life processes (e.g., humans)

Seven Characteristics of Life

• Movement

• Reproduction

• Sensitivity

• Growth

• Respiration

• Excretion

• Nutrition

• The Gas Exchange System

Stages for Gas Exchange:

• Air is inhaled through the mouth and enters the lungs
• Oxygen diffuses through the alveoli into the bloodstream
• Oxygen is transported in the bloodstream to respiring cells
• Oxygen is used in aerobic respiration
• Carbon dioxide diffuses out of respiring cells into the bloodstream
• Carbon dioxide diffuses out of the bloodstream into the alveoli and is exhaled

Diagram of Gas Exchange System

• Contains alveoli, trachea, bronchioles, intercostal muscles, a left and right bronchus, ribs, and diaphragm

Alveoli

• Gases pass into and out of the alveoli using diffusion
• Oxygen moves from the alveoli to the capillaries
• Carbon dioxide moves from the capillaries to the alveoli

Lungs for Efficient Gas Exchange

• Possess a large surface area to increase the rate of diffusion
• Alveoli have walls that are one cell thick for a short diffusion distance
• Good blood supply maintains the concentration gradient

Breathing in

• The diaphragm contracts and moves down to decrease pressure in the chest and allow air to be drawn in.

• The intercostal muscles also contract, causing the ribs to move up and out

• These actions increase the space in the lungs

• Heart Diagram and Harmful Chemicals

Measuring Vital Capacity

• Take a deep breath in and exhale into a lung volume bag, then compress the air out of the bag. Record the resulting volume.

Heart Tissue

• The heart is mostly made of muscle tissue.

Blood Vessels

• Arteries transport blood away from the heart, and veins transport blood towards the heart

Difference between Left and Right Sides of the Heart

• The left side of the heart contains oxygenated blood, while the right side contains deoxygenated blood.

Frog’s Heart Disadvantage

• A frog's heart allows blood on the left and right sides to mix, making oxygen transport less efficient than in a human heart.

Harmful Chemicals in Cigarette Smoke

• Nicotine is addictive and raises blood pressure
• Tar sticks cilia together
• Carbon monoxide binds to red blood cells and prevents oxygen transport

Activity During and Following Exercise

• During exercise, heart rate increases due to the increase in oxygen required
• After exercise, heart rate returns to normal resting rate
• Breathing remains heavy to repay the oxygen debt