SNC2 Biology Review.

SNC2 Biology Review

What is an Organism? An organism is a living thing. It is easy to recognise a living thing, but not so easy to define it. Animals and plants are organisms, obviously. Organisms are a biotic, or living, part of the environment. Rocks and sunshine are parts of the non-living environment abiotic.

Know the difference between
Quark: Simply energy. Can’t be seen under any microscope. Atom: Made from quarks. Has protons, neutrons. These make molecules. Molecule: These are made from Atoms. Examples of molecules are: Hydrogen, Oxygen. Organelle: Made of molecules and are the small organs in each cell. Examples in animal cells are: Nucleus, Ribosome, Lysosome. Cell: Made up of organelles. Cells are the building blocks of life. Tissue: Made from similar cells. Each organ has specific types of cells that make that particular organ and its parts. Organ: Similar types of tissue (example muscle tissue, heart tissue) makeup an organ. Organ System: Organs that work together to help an organism execute a specific function (breathing, thinking, etc) are part of an organ system. Organism: An organism is the person/thing.

Nucleus The nucleus is the large control centre of a cell, directing all of the cell's activities. Chromosomes that contain your DNA are stored in this organelle. The nucleus is separated from the rest of the cell by the nuclear membrane.

Ribosome Found on the endoplasmic reticulum or free in the cytoplasm.
Proteins are made in this organelle.

Mitochondria The mitochondria is sometimes referred to as the powerhouse of the cell. Mitochondria are largely responsible for providing the cell with energy from glucose (sugar) through a process called cellular respiration.

Golgi Bodies Golgi bodies collect and process materials to be removed from the cell. They also make and secrete mucus. Cells that secrete a lot of mucus, such as cells lining the intestine, have many Golgi bodies.

Endoplasmic Reticulum
The endoplasmic reticulum is a three-dimensional network of branching tubes and pockets. It extends throughout the cytoplasm from the nuclear membrane. These fluid-filled tubes transport materials, such as proteins, through the cell.

Chloroplast Looks like: green stacks of membranes that contain chlorophyll Job: perform photosynthesis (convert sunlight into energy) 9

Vacuole Looks like: sac-like organ. HUGE in plant cells
Job: stores water, food, and waste 10

Vesicles A vesicle can be seen as a bubble of liquid within a cell.
It is a small membrane-enclosed sack that can store or transport material.

Cell Membrane Looks like: layered membrane surrounding the
cell but inside of the cell wall Job: “the regulator”-controls what comes in and out of the cell, protects, and supports the cell 12

Cell Wall Looks like: thick layer outside the plasma membrane
Job: structure and support 13

Nuclear Membrane

What is the Cell Cycle? As eukaryotic cells grow and divide, they pass through a cell cycle that consists of 3 stages: Interphase Mitosis (cell division) Cytokinesis (cell division)

What happens?

STAGE of CELL CYCLE

Stage 1: Interphase Interphase is the longest stage of the cell cycle
The cell performs its normal functions and, in preparation for cell division, duplicates its genetic material (DNA)

Stage 2: Cell Division - Mitosis
Consists of 4 phases: Prophase Metaphase Anaphase Telophase

Mitosis Phase 1:Prophase
DNA compacts into visible form as chromosomes Each chromosome contains two strands called sister chromatids. Sister chromatids are held together by a centromere The nuclear membrane breaks down

Mitosis Phase 2: Metaphase
Chromosomes line up in the middle of the cell.

Mitosis Phase 3: Anaphase
The centromere splits and sister chromatids separate. They are now called daughter chromosomes. They move to opposite ends of the cell, pulled by spindle fibres

Mitosis Phase 4: Telophase
Final phase of mitosis. Chromosomes stretch out and are no longer visible. A new nuclear membrane forms around each group of daughter chromosomes.

Stage 3: Cell Division - Cytokinesis
Final stage of cell division and cell cycle The cytoplasm divides and two genetically identical cells are formed. In a plant cell, a plate develops into a new cell wall In an animal cell, the cell membrane is pinched off in the centre

Plant vs Animal (Cytokinesis)
In a plant cell, a plate develops into a new cell wall In an animal cell, the cell membrane is pinched off in the centre forming two membranes,

1. Plant cells have a cell wall, Animal Cells do not
Plant vs. Animal Cells There are three main differences between plant and animal cells: 1. Plant cells have a cell wall, Animal Cells do not 27

2. Plant cells have chloroplasts and Animal Cells do not
Plant vs. Animal Cells 2. Plant cells have chloroplasts and Animal Cells do not 28

3. Plant cells have larger vacuoles (storage spaces)
Plant vs. Animal Cells 3. Plant cells have larger vacuoles (storage spaces) 29

Plant vs. Animal Cells Plant Cells Chloroplasts Cell wall
Large vacuole Animal Cells No Chloroplasts No Cell wall Small Vacuole 30

Plant vs. Animal Cells Different Shapes (Plants are rectangles, and Animals are round) 31

Stages of Pregnancy and Development
Fertilization Embryonic development - Cleavage Fetal - Differentiation Growth – Development Childbirth

Fertilization The egg is viable for 12 to 24 hours after ovulation
Sperm are viable for 12 to 48 hours after ejaculation Sperm cells must make their way to the uterine tube for fertilization to be possible

ZYGOTE The sperm and egg join to form a zygote: the first cell of a new individual. Zygote results of the fusion of DNA from sperm and egg 2. Fertilization occurs in the Fallopian Tubes 3. The zygote begins rapid mitotic cell division 4. Beginning of human development

Differentiation EMBRYO
0.5 cms 20 days after fertilization Embryo begins to form organs during the third week. Cannot tell if it is human or other vertebrate. Tall visible.

Differentiation Ears, nose and eyes not visible
EMBRYO 1 months 0.6 cms Ears, nose and eyes not visible Small arm and leg buds, backbone seen Heart beats.

Differentiation During the second month most of the major organ systems form, limb buds develop. Limbs distinct with fingers and toes bones begin to form, eyes far apart. The embryo becomes a fetus by the seventh week. FETUS 2 months 3 cms

Differentiation All organ systems are formed by the end of the eighth week Activities of the fetus are growth and organ specialization A stage of tremendous growth and change in appearance Fetus at nine weeks 3 cm

Differentiation Beginning the eighth week, the sexually neutral fetus activates gene pathways for sex determination, forming testes in XY fetuses and ovaries in XX fetuses. External genitalia develop. FETUS 2 months 3 cms

Developmental Aspects of the Reproductive System
Gender is determined at fertilization Males have XY sex chromosomes Females have XX sex chromosomes Gonads do not begin to form until the eighth week Slide 16.64a Copyright © 2003 Pearson Education, Inc. publishing as Benjamin Cummings

Four Basic Kinds of Tissues
Epithelial Tissue Connective Tissue Muscle Tissue Nervous Tissue

Epithelial Tissue Epithelial Tissue Locations:
Covers the body Lines the cavities, tubes, ducts and blood vessels inside the body Covers the organs inside body cavities Epithelial Tissue Functions: Protection from physical & chemical injury, Protection against microbial invasion, Examples: Skin, small intestine

Connective Tissue Connective Tissue:
Most abundant & widely distributed tissue Connective Tissue Functions: Connects, binds and supports structures, Tendons, ligaments, etc. Protects & cushions organs and tissues, Insulates (fat) and Transports substances (blood). Example: Bone and Blood.

Muscle Tissue Muscle Tissue:
Associated with the bones of the skeleton, the heart and in the walls of the hollow organs of the body. Muscle Tissue Functions: Movement Locomotion Maintains posture Produces heat Facial expressions Pumps blood Peristalsis Example: arm, stomach, heart

Nervous Tissue There are three types of neurons, sensory neurons
Main component of the nervous system, ie., brain, spinal cord & nerves. Nervous Tissue Functions: Regulates & controls body functions Generates & transmits nerve impulses Supports, insulates and protects impulse generating neurons. There are three types of neurons, sensory neurons motor neurons. connector neurons

Cell Specialization All cells carry the same DNA information but they do not perform the same functions and may not look the same. All cells start their lives as identical cells called stem cells. The process of a cell becoming a particular type of cell is called cell differentiation.

Groups of cells that function together and are specialized for common tasks are called tissues.
In simple terms, they are groups of cells that work together to do the same job

Human Organ Systems 48

Levels of Organization
Remember, the human body is organized in several levels, from the simplest to the most complex. . . Cells – the basic unit of life Tissues – clusters of cells performing a similar function Organs – made of tissues that perform one specific function Organ Systems – groups of organs that perform a specific purpose in the human body ***The purpose of the 11 organ systems is for the human body to maintain homeostasis. 49

Homeostasis Homeostasis is: The ability or tendency of an organism or cell to maintain internal equilibrium by adjusting its physiological processes.

The 11 Human Body Systems The 11 human body systems are as follows:
-- nervous system -- integumentary system -- respiratory system -- digestive system -- excretory system -- skeletal system -- muscular system -- circulatory system -- endocrine system -- reproductive system -- lymphatic (immune) system 51

The Digestive System Purpose: to convert food particles into simpler micromolecules that can be absorbed into the bloodstream and used by the body Major Organs and their Functions: Mouth – to chew and grind up food -- saliva also begins the chemical breakdown Esophagus – pipe connecting mouth to stomach Stomach – secretes an extraordinarily strong acid (pH = 2) that leads to breakdown of food -- once the food is broken down in the stomach and mixed with digestive juices, it is called chyme 52

-- also help neutralize stomach acid
Pancreas – produces the hormone insulin that regulates blood sugar levels -- also help neutralize stomach acid Liver – produces bile, which breaks down fats in foods Gallbladder – pouch-like organ that stores bile for future use Small Intestine – after digestion is complete, the chyme enters the small intestine where it is absorbed into the bloodstream -- the chyme is propelled along by folded surfaces called villi, on the intestine Large Intestine – removes water from the chyme and gets the waste ready for excretion 53

The Digestive System 54

The Respiratory System
Purpose: to provide the body with a fresh supply of oxygen for cellular respiration and remove the waste product carbon dioxide Major Organs and Their Functions Nose – internal entry and exit point for air Pharynx – serves as a passage way for both air and food at the back of the throat Larynx – your “voicebox”, as air passes over your vocal chords, you speak Trachea – the “windpipe”, or what connects your pharynx to your lungs -- a piece of skin, called the epiglottis, covers the trachea when you swallow, preventing food from entering 55

-- the bronchi are further subdivided into bronchioles
Bronchi – the two large passageways that lead from the trachea to your lungs (one for each lung) -- the bronchi are further subdivided into bronchioles -- eventually, the further subdivisions lead to tiny air sacs called alveoli -- alveoli are in clusters, like grapes -- capillaries surrounding each alveolus is where the exchange of gases with the blood occurs The diaphragm is the muscle that causes you to breath -- hiccups are involuntary contractions of the diaphragm 56

Image of the Respiratory System
57

The Circulatory System
Purpose: to deliver oxygenated blood to the various cells and organ systems in your body so they can undergo cellular respiration Major Organs and Their Functions Heart – the major muscle of the circulatory system -- pumps blood through its four chambers (two ventricles and two atria) -- pumps deoxygenated blood into the lungs, where it gets oxygenated, returned to the heart, and then pumped out through the aorta to the rest of the body -- valve regulate the flow of blood between the chambers 58

Capillaries – small blood vessels where gas exchange occurs
Arteries – carry blood away from the heart and to the major organs of the body Veins – carry blood back to the heart away from the major organs of the body Capillaries – small blood vessels where gas exchange occurs Blood – the cells that flow through the circulatory system -- red blood cells contain hemoglobin, an iron-rich protein that carries oxygen -- white blood cells function in the immune system -- platelets help in blood clotting Spleen – helps to filter out toxins in the blood 59

Image of the Circulatory System
60

THE HUMAN HEART The human heart consists of 4 chambers
there are two types of chambers: the atrium and the ventricle there are two of each type in the heart the heart weighs a mere 300 grams -the heart weighs 300 grams -it's about the size of a fist -it has 2 atria -it has 2 ventricles -the walls of the ventricles are seperated by the interventricular septum

HEART VALVES The human heart contains valves which prevent blood from flowing back into the heart chambers after it has contracted atrioventricular valves are found between the atrium and ventricle of each side of the heart semilunar valves are found in the arteries leaving the heart to prevent blood from flowing back into the ventricles

HEART AT WORK Each minute of the day the heart pumps 5 litres of blood
each time the heart beats it sends deoxygenated blood to the lungs and oxygenated blood to the body

THE HEART TO THE LUNGS Blood enters the right atrium of the heart via two large veins: the superior vena cava and the inferior vena cava blood exits the right ventricle of the heart through the pulmonary artery to the lungs

Direction of Blood

THE HEART TO THE BODY (Circulatory and Respiratory)
Blood reenters the left artrium of the heart via the pulmonary vein blood on the left side of the heart is oxygenated and is pumped into the body by the left ventricle through the aorta

What is cancer? Caner is defined as the continuous uncontrolled growth of cells. A tumor is a any abnormal proliferation of cells. Benign tumors stays confined to its original location Malignant tumors are capable of invading surrounding tissue or invading the entire body Tumors are classified as to their cell type Tumors can arise from any cell type in the body

What is Melanoma? A type of skin cancer Some risk factors include:
Sun exposure -depleting ozone layer Presence of many or unusual moles Skin types Genetics predisposition Nonetheless there are risks factors that highly attributed to its incidence. Some of the them are: amount of sun exposure – the more cumulative exposure the higher presence of many of unusual mole – people with many moles in the body Fitzpatrick’s Skin Type I and II have higher risk –1975 Thomas Fitzpatrick, Harvard skin typing system based on skin complexion and response to sun exposure genetic predisposition – if there history of melanoma that runs in the family According to a study ,compared to general population, people who with 2 risk factors have 3.5 times risk of developing MM and 20 times those who have 3 or more risk factors. 68

skin benign malignant

E= evolution/elevation
What to say ABCDE system is the tool for detecting melanoma. This is a list of criteria that can be used for distinguishing between benign and malignant melanocytic skin lesions. A- if you draw a line across the center of MM, you’ll see that is not symmetric compared to regular mole B- the border is uneven or ragged is a sign of melanoma C-if there are multiple shades of pigment is presence D- diameter > 6mm Dermatologist adds E for either evolution if lesion changes upon observation or E for elevation. Suspicious lesion is followed by histological confirmation. 70

Diagnosis and Medical Imaging Technology
SNC2D

Diagnosis The interdependence of our organ systems can sometimes make it difficult to pinpoint the source of a medical problem. Doctors are trained to look for symptoms that are characteristic of specific problems.

Diagnosis The interdependence of our organ systems can sometimes make it difficult to pinpoint the source of a medical problem. Doctors are trained to look for symptoms that are characteristic of specific problems (e.g. swollen lymph nodes are a symptom of infection).

Tools of the Trade To collect information about what’s going on inside the body, doctors may use devices like the stethoscope (to listen to the heart and lungs)

Tools of the Trade To collect information about what’s going on inside the body, doctors may use devices like the stethoscope (to listen to the heart and lungs) and a sphygmomanometer (to measure blood pressure).

Tests of the Trade Doctors may also order tests of material collected from the body (such as blood and urine) which may be analyzed by a separate lab. E.g. Blood may be tested to determine the levels of red blood cells, white blood cells, sugar, and hormones – the chemicals that carry messages through the body to regulate the functioning of organs.

Medical Imaging Technologies
Diagnostic imaging tests can provide doctors with even more information: an actual visual picture of the structure and functioning of organs. However, these technologies are often expensive, and the effectiveness of each technology is limited by its properties.

Endoscopy An endoscope is a thin, flexible tube that has a bright light and a video camera that can be used to image the digestive tract, as in a colonoscopy.

Thermography In thermograms, infrared light cameras are used to diagnose problems with circulation. Normal Raynaud’s syndrome

X-Rays X-rays are high-energy electromagnetic radiation that can easily penetrate soft tissues but cannot easily penetrate bone.

X-Rays X-rays are used to check for cancers (e.g. mammograms), to diagnose problems in the circulatory and respiratory systems, and to check for broken bones. They are quick, painless, and non-invasive but exposure to x-rays can damage cells and increases cancer risk.

Body Scanners Note that this is also true for the body scanners that are used at airports, especially the new “naked body scanners.”

Body Scanners Since the radiation emitted by these body scanners is absorbed at the level of the skin, it is your skin cancer risk that is most increased – and the scans cannot find anything concealed in any body cavity.

Body Scanners Since the radiation emitted by these body scanners is absorbed at the level of the skin, it is your skin cancer risk that is most increased – and the scans cannot find anything concealed in any body cavity. Also, like most x-rays, they do not show contrast that may be used to identify soft materials (like plastics and chemical explosives).

Body Scanners Since the radiation emitted by these body scanners is absorbed at the level of the skin, it is your skin cancer risk that is most increased – and the scans cannot find anything concealed in any body cavity. Also, like most x-rays, they do not show contrast that may be used to identify soft materials (like plastics and chemical explosives). In other words, they’re completely ineffective.

Computed Tomography Computed tomography (CT) scans, also called computer-assisted tomography (CAT) scans, use x-rays to produce images at different angles through the body so that a 3D image can be constructed.

Computed Tomography CT scans may be used to diagnose cancers, skeletal abnormalities and vascular diseases (affecting blood vessels). But since CT scans use x-rays, they also increase your cancer risk.

Fluoroscopy Fluoroscopy is a technique in which a continuous beam of x-rays is used to produce moving images. It is used to show movement in the digestive system (which may require ingestion of a high-contrast liquid such as barium) and the circulatory system (angiograms).

Ultrasound Ultrasound is high-frequency sound waves produced by a device called a transducer that are reflected back to the transducer by internal body structures.

Ultrasound Ultrasound is used to study soft tissues and organs, especially the heart (echocardiograms) and especially during pregnancy. Because the presence of gas can distort images, ultrasound is not often used for imaging the respiratory or digestive systems.

Magnetic Resonance Imaging (MRI)
Magnetic Resonance Imaging (MRI) is a technique that uses strong magnets and radio waves that interact with the hydrogen atoms in your body (esp. in water). A computer is used to construct an image from the signal received from the atoms.

Magnetic Resonance Imaging (MRI)
MRI is used to image the structure and function of the brain, heart, soft tissue, and the inside of bones; to diagnose cancers, brain diseases, and problems with the circulatory system. But it is also extremely expensive and the availability of machines/technicians is limited.

Positron Emission Tomography (PET)
PET scans are a type of nuclear medicine is which a patient is given a radioisotope that emits positron radiation; the radioisotope is attached to a chemical absorbed by certain tissues or organs. It is used to detect cancers, heart disease, and some brain disorders (such as Alzheimer’s).

End!!!!

SNC2 Biology Review.

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