SNC2D Grade 10 Academic Science – Biology Notes

Thanks, Jennifer!

 

SNC2D Biology Review

Cell Theory:
-all living things are made up of at least one or more cells and their products -the cell is the simplest unit that can carry out life processes
-all cells come from other cells; they do not come from non-living matter

Types of Cells: Prokaryotic:
-single celled life forms -simple, primitive cells -no nucleus or organelles -ex. bacteria and archaea

Eukaryotic

-single or multicellular organisms
-more complex and larger
-do have nucleus and organelles
-make up multicellular organisms like plants, fungi

Limitations of Cell Size
-as a cell grows bigger, the ratio or the area and volume decrease meaning the cell will not have enough room for nutrients
-the cell membrane must be large enough to support the cell volume

Organelles

Cytoplasm

-suspends organelles -fluid,jelly, liquid filling

Cell Membrane

-supports cell
allows diffusions of unwanted substances -semi-permeable membrane

Nucleus

-spherical
-contains all DNA and genetic info

Mitochondria

-powerhouse of cell
-makes energy available for the cell -converts glucose to energy

Endoplasmic Reticulum (ER)

-3-D network of branching tubes that transport materials throughout the cell

Golgi Body (Apparatus)

-secretes mucus
-collects and removes unwanted materials -has a stacked structure like pancake

Vacuole

-contains substances, isolates and removes waste, maintains internal fluid pressure

Cell Wall (plants)

-helps plant hold its shape
-found outside the cell membrane

Big Vacuole (plants)

-full of water to keep stem and leaves firm -isolates and removes waste

Chloroplast

-absorbs light for photosynthesis to occur -has chlorophyll that gives green colour

Cell Division
-growth (cells can’t grow too big) -repair
reproduction (sexual and asexual)

The Cell Cycle
-eukaryotic cells grow and divide

Interphase

-cell performs normal functions

-genetic material and DNA copied -DNA is doubled

Mitosis: Prophase

-long strands of DNA condense into compact form called chromosome -DNA shortened and thickened
-nuclear membrane splits

Mitosis: Metaphase

-chromosomes line up in centre of the cell, held by spindle fibres in order for mitosis to continue

Mitosis: Anaphase

-centromere splits and sister chromatids separate -appeared to be pulled apart
-daughter chromosomes move to opposite ends of cell

Mitosis: Telophase

-new nuclear membrane forms
-daughter chromosomes unwind and stretch out to become stringy masses -two nucleis

Cytokinesis

-final stage
-organelles divide producing two identical daughter cells -in plants, plate develops between two cells called cell wall -in animals, cell membrane is pinched off in the centre

Chromatid: half of a chromosome
Chromosome: organized bundle of DNA
Chromatin: messy bundle of DNA
Centromere: holds two chromatids together to create a chromosome
Spindle Fibres: controls the movement of chromosomes, are scaffolding for the cell, doesn’t remain fixed, originate from the centrioles

Cancer
-cell division gone wrong
-cells divide rapidly ignoring the body’s chemical reactions telling cell not to divide -changes in DNA that controls cell cycle

Tumours

Benign:

-stays together, no serious effects to surrounding tissue -not cancerous

Malignant:

-interferes with functions of neighbouring cells -cancerous

Metastasis:

-cancer cells break away from the tumour to settle into other parts of the body -cancerous

Carcinogens
-factors that can cause mutation (random change in DNA), leading to cancer -ex: tobacco smoke, radiation, viruses, chemicals in plastics
-some cancers have a genetic/hereditary link

Diagnosing Cancer

Imaging

-endoscopy (fibre optics)

-x-ray (viewing bones and lungs)
-ultrasound (sound waves for soft tissue view)
-CT scan (x-rays at different angles)
-MRI (radio waves and magnetic field generate images)

Examining Cells

-biopsy (sample of cells), viewed with microscope and genetic tests

Treating Cancer

Oncologist

-specializing in cancer medicine

Surgery

-surgically removing cancerous cells

Chemotherapy

-using drugs to travel through body and target different cells -shrink or slow the growth of tumour
-linked with surgery

Radiation

-cancer cells damaged easily by ionizing radiation -daughter cells are damaged and cannot divide further

Biophotonics

-using beams of light to detect cancer early and treat

Hierarchy: organizational structure with more complex things at top and simpler things below it

Organization of Organism
1. Cell ( ex. heart muscle cell)
2. Tissue ( collection of similar cells to perform particular but limited function. ex. heart

muscle tissue)
3. Organ ( structure composed of different tissues to perform complex function. ex. heart)
4. Organ System ( system of one or more organs and structures that work together for a major

body function. ex. digestion, circulatory)

Tissues

Epithelial

-thin sheets of tightly packed cells that covers body surfaces and lines internal organs -protection from dehydration
-ex. skin, lining of digestive system

Connective

-specialized tissue that provides support and protection for various parts of the body -support and insulation
-ex. bones, tendons, blood

Muscle

-specialized tissue containing proteins that can contract and enable body movement -ex. heart, muscles that make bones move

Nerve

-specialized tissue that can conduct electrical signals from one part of the body to another -sensory, communication, coordination
-ex. brain, nerves in sensory organs

Cellular Differentiation:
-process where a cell becomes specialized to perform specific function -an animal cell can differentiate into many cells called stem cells

Stem Cells: an undifferentiated cell that can divide to form specialized cells
Embryonic Stem Cells: can differentiate into any kind of cell
Tissue Stem Cells: exist within specialized tissue, only able to differentiate into certain types of cells

Skeleton
-supports and protects body
-provides structure
-anchor for muscles
-store calcium and minerals
-bone marrow that produces red and white blood cells -allows movement
-consists of bones, ligaments, cartilage

Ligaments: connects bone to bone, holds bones together at joints
Cartilage: dense connective tissue that provides support (ex. ear, nose)

Tendon: less elastic than ligaments, connect muscle to bones

Spine: central support for body, made of vertebrae Hands & Feet: bones with flexibility (hands: carpals, metacarpals, phalanges; feet: tarsals, metatarsals, phalanges)

Ribs: protect heart and lungs
Hips & Legs: for movement and posture (bones are tibia, fibula, femur, patella) Arms: flexibility (ulna, radius, humerus, clavicle, scapula)

Types of Bones
Long: l onger than wide (ex. femur, humerus) Short: about as long as wide (ex. carpals, tarsals)
Flat: f lat plates (ex. scapula, sternum)
Irregular: n on-uniform shape (ex. mandible, vertebrae) Sesamoid: embedded in tendon (patella)

Axial Skeleton
-skull bones, vertebrae, ribs, sternum

Appendicular Skeleton
-bones of pectoral girdle, pelvic girdle, upper and lower limbs

Joints
Hinge: f lexion, extension (ex elbow/knee)
Pivot: p ivot, turn, rotate, move (ex. top of neck)
Ball and Socket: f lexion, internal/external rotation (ex. shoulder, hip) Saddle: f lexion, extension, adduction, abduction, circumduction (ex. thumb)

Muscles
-composed of muscle fibres arranged in bundles
-proteins cause contraction
-skeletal muscle: under voluntary control
-smooth muscle: involuntary (ex. intestines)
-cardiac muscle: located in heart
-nerve impulses causes muscles to contract and move bones -muscles can pull but not push, WORK IN PAIRS

Systems
Digestive: system that digests food and excretes waste (mouth, esophagus, stomach, intestines, liver, pancreas, gall bladder)
Circulatory: t ransports oxygen and nutrients throughout the body and carries away waste (heart, blood, blood vessels)
Respiratory: p rovides oxygen for the body and allows for CO2 to leave (nose, mouth, bronchi, trachea, lungs)
Musculoskeletal: supports body, supports delicate organs, allows movement (bones and skeletal muscle)
Nervous: senses the environment and coordinates responses (brain, spinal cord, peripheral nerves) E n d o c r i n e : s e c r e t e s h o r m o n e s t o c i r c u l a t o r y s y s t e m ( g l a n d s )
Urinary: eliminates waste and regulates blood and liquid in body (kidneys, ureters, bladder, urethra)
Integumentary: protects body from damage (skin and its appendages like nails and hair) Reproductive: f or sexual reproduction (sex organs)

Interactions of Systems

Digestive and Circulatory

-digestive breaks down food into small molecules that pass through the walls of the digestive tract -without the circulatory system, only tissues next to the digestive tract will receive the nutrients -circulatory provides transportation of nutrients all around the body
ex. capillaries surround digestive tract to carry blood that absorbs the nutrients

Musculoskeletal and Respiratory

-skeletal muscle tissue uses oxygen and nutrients to move
-every muscle contraction, the rate of cellular respiration increases

-to fuel the active system, circulatory must deliver a constant supply of oxygen and nutrients with the respiratory system working together to remove CO2 waste

SEXUAL REPRODUCTION
-2 parents and a unique offspring
-responsible for variation between individuals
-meiosis
-two haploid cells (sexcells/gametes) combine to reproduce a diploid cell (eventually becoming unique offspring)

Diploid (2): c ell or organism with 2 sets of chromosomes, 1 from each parent (46 chromosomes) Haploid (1): c ell or organism (sex cells) has half the number of chromosomes (23 chromosomes)

Gametes
-haploid male/female sex cell -egg/sperm cell
-produced through meiosis

SEQUENCE OF SEXUAL REPRODUCTION

  1. Meiosis between male and female produces haploid gametes (egg/sperm) in gonads

    (ovaries, testes)

  2. Male gamete combines with female gamete
  3. A z ygote (diploid cell formed by combination of two gametes) is produced then further

    developed into an e mbryo (multicellular diploid eukaryotic cell in earliest stages of

    development)

  4. Embryo develops into a mature and unique offspring from mitosis and cell division.

Development of Sperm
1. Hormonessignalspermtodevelopinthes eminiferoustubulesinthetestes .
2. Epididymus receives sperm and stores it for several days
3. Ejaculation causes sperm to forcefully expel from the tale of the epididymus into the vas

deferrens
4. Seminalvesicles/p rostate: secretionsareaddedtosperm,spermbecomessemen
5. Semen passes through urethra and is ejaculated through the far end of the u rethra

Development & Pathway of Egg
1. Egg (ovum) is released into the o vary (follicle)
2. Follicle matures and releases egg into fallopian tubes
3. If fertilized. egg (zygote) remains in fallopian tubes then develops into a cluster of cells,

implanting in the u terus for development.

Plants
-multicellular organisms
-eukaryotic (have nucleus and organelles)
-immobile
-autotrophic
-can reproduce sexually and asexually
-must exchange gasses, absorb water and nutrients to transport as food

-do not need complex systems to hunt for their food

Shoot System
-system in flowering plant that is specialized to photosynthesize and reproduce
-consists of:
Leaf: main photosynthetic organ, organelles in leaf have chloroplasts for photosynthesis, have been adapted for protection, reproduction, and chloroplasts
Stem: main function is to support leaves and flowers, connects leaves to roots, transports sugar from leaves to roots, transports water and minerals and nutrients from the roots to the leaves Flower: designed for sexual reproduction, can be male/female/both, pollination occurs through wing, insects, birds, etc.

Root System
-system in flowering plant that anchors plant, absorbs water and minerals, stores food -water and nutrients are sent up to leaves through xylem
Fibrous Roots (monocots)
-adapted to increase surface area for absorption
-shallow depth in soil
-ex. grass, lilies

Tap Roots (dicots)

-adapted to anchor plants and for storage -grows deeper into the soil
-ex. carrot, tree, dandelion

Plant Tissues

Dermal Tissue

-forms outer layer of plant (epidermis) for protection
-epidermal leaf cells produce waterproof cuticle which stops intruders
-cuticle: layer of wax on the upper and lower surfaces of the leaf that blocks the diffusion of water and gasses

Vascular Tissue

-for circulation of minerals, nutrients, water

1. XYLEM

-transports water and dissolved materials from the roots up to the leaves -elongated cells join to make tubes

2. PHLOEM

-transports products of photosynthesis all around the plant -elongated cell like tubes remain alive at maturity

Ground Tissue

-the “filler” located between the dermal and vascular tissue
-performs functions of photosynthesis, food and water storage, and structural support

Periderm tissue: t issue on the surface of a plant that produces bark on stems and roots Epidermal tissue: thin layer of cells covering all non-woody surfaces of the plant

Meristematic Cell: an undifferentiated plant cell that can differentiate to form specialized cells, similar to animal stem cells, ONLY PLANT CELL THAT UNDERGOES MITOSIS

*purpose of cell division in cells: grow in size, shape, perform functions, have plants grow and reproduce through meiosis*

Apical Meristem: undifferentiated cell at tips of plant’s shoots and roots; cells that divide and enable the plant to grow longer/taller and develop into specialized tissues

Lateral Meristem: undifferentiated cell under the bark in the stems and roots of woody plants; cells that divide and enable the plant to grow wider and develop specialized tissues in the stem

Tissues working together
-stem, leaf, and flower all work together to do its main job of feeding itself (photosynthesis)

Absorbing light and gasses
– x y l e m i n v a s c u l a r t i s s u e b r i n g s t h e w a t e r t o m e s o p h y l l t i s s u e s o f t h e l e a f a n d t h e g u a r d c e l l s o f t h e stomata a llow for CO2 to enter
-water and CO2 go through photosynthesis in the chloroplasts of the leaves
-the glucose made from photosynthesis transfers to the vascular bundle/vein and into the phloem to send the food for the roots, meristem tissue, and fruit
-g uard cells controlling s tomatal pore a re responsible for gas exchange
-guard cells open and close to allow CO2 in when photosynthesis can occur and let O2 out

Palisade Layer

-layer of tall, closely packed cells containing chloroplasts -just below the upper surface of the leaf

-type of ground tissue

Spongy Mesophyll

-under the palisade layer of the leaf
-c irculates air and exchange of gas
-a region of loosely packed cells containing chloroplasts -in the middle of the leaf
-type of ground tissue

Guard Cells

-one pair of special cells in the epidermis (epidermal tissue) -surrounds the stomata to let gas in

Stomate (plural stomata)

-an opening in the surface of a leaf that allows for exchange of gasses -surrounded by two guard cells

Vegetative Reproduction
-asexual reproduction (cloning)
-process where a plant produces a genetically identical offspring from its roots or shoots
-ex. strawberries sent long ‘runners’ that can grow into new roots using the meristems in the tips of these ‘runners’