Download Year 10 Revision

Year 10 Revision
Instructions
There are multiple choice questions. Answer these on the answer sheet that is provided.
Each question is worth 1 mark. Answer all questions. Marks will NOT be deducted for
incorrect answers.
The short answer questions should be answered in the spaces provided. The marks
allocated for each question are included. This section is worth 70 marks.
Total marks for the exam is 100.
You are allowed a Scientific Calculator only and a hand written one sided A4 cheat sheet.
Cell Biology
Understand the Cell Theory
Developed in 1838 the Cell Theory
is the most basic condition for
determining if something is alive.
• All things made of cells,
• Cells come from pre-existing cells
and
• Cell basic unit of life.
• Cells make up tissues and organs
and organisms
• Identify the similarities and differences between
Prokaryotes and Eukaryotes. (eukaryotes have
organelles compartments for specialised functions.
All cells have membrane, DNA, cytoplasm and
ribosomes)
• Eukaryotes, unlike the prokaryotes, contains nuclei,
and several other membrane-bound organelles.
• Both are cells with cell membranes and cytoplasm
and genetic material.
• Only Eukaryotes have membrane bound organelles
and are generally multicellular
Identify the function of the main organelles: nucleus, mitochondria,
chloroplasts, ribosomes, golgi complex, endoplasmic reticulum.
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Plasma Membrane--Found in all cells and made of a double layer (a bilayer) of phospholipids and
controls what substances enter and leave the cell.
Golgi bodies--These look like stacks of water-balloon-pancakes and are sort of like the shipping and
receiving department within the cell.
Vacuole--Organelle that takes up most of the space within the plant cell and is used for storage of
all sorts of molecule, especially water.
Mitochondria--Found in nearly all eukaryotic cells, usually several or many per cell. They burn sugar
for fuel in the process of cellular respiration.
Ribosomes--Small special organelles that are directly involved in protein synthesis. They’re not
membrane bound, but are organelles.
Endoplasmic Reticulum--There are 2 kinds of ER: smooth ER and rough ER. Chemicals like proteins
the cell has manufactured are stored in the lumen for transportation elsewhere in the cell
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Chloroplasts--Organelles that convert light energy (from the sun) to chemical energy via the process
of
Chlorophyll-Green Pigment-Used by a plant to capture energy from the sun, which can later be
used to create food.
Cytoskeleton--Made of various types of special proteins and provides the structural support in the
cell.
Centrioles--Animal cells typically have a pair of these tiny organelles located just outside the
nucleus and oriented at right angles to each other. These function in cell division.
Lysosomes--Organelles found in animal cells and contain strong enzymes. Used to kill off or recycle
the cell or organelles.
Nucleus--Control center of the cell contains all the genetic material. Large Organelle
Cell Wall--This is the outermost layer in the plant cell. It is stiff, rigid, nonliving, and made of
cellulose.
Cytosol-It contains and supports the cell organelles.-A thick, jellylike substance found in all cells
filling the space between the nucleus and the cell membrane.
What are the characteristics of Plant and
Animal Cells: similarities and differences.
DNA and Chromosomes
Describe and draw components of DNA
• building blocks nucleotides,
• double helix,
• base pairing rule
The shape of DNA at the molecular level is thought to look like a gently twisting ladder.
Each of the rungs on the ladder represents a chemical bond between the chemicals that
make up the DNA molecule.
These chemicals are called nucleotides.
There are 4 types of Nucleotides that repeat and
make up DNA.
Adenine (A);
Thymine (T);
Cytosine (C); and
Guanine (G)
DNA is said to be “double-stranded” because it is made up of two sequences of nucleotides
that are tightly connected together by chemical bonds. The chemical bond between the
nucleotides always exists between A and T and G is always bound to C.
For example;
Strand 1: C – A - G – C - A – T – T – G
Strand 2: G – T - C - G - T - A - A – C
Chemical bonds exist between strand 1 and strand 2 that connect the nucleotide pairs The
strands are complimentary to one another, by knowing the sequence to one you can figure
out the other
Identify the function of DNA
Genes
Proteins
Genotype
Each Body cell contains 46 DNA molecules that form 46 chromosomes or 23 Chromosome
pairs. DNA molecules are essentially long strands of repeated Nucleotide codes and sections
of DNA that make different proteins are called Genes.
One gene is responsible for one function in one type of cell. For example one gene is
responsible for our eye colour. This eye colour gene sits on the same part of DNA in every cell
in the body however it is only the in the cells that make up the iris that that gene will be
expressed.
All the genes and genetic information required for life contained in a cell is called the cell’s
genome and thanks to the Human Genome Project we now know that humans have 30000
genes.
List the differences between DNA and RNA
DNA- Made of
nucleotides
Bases are TACG, double
stranded, in nucleus
and sugar is
deoxyribose. Contains
the template and
complementary strand
RNA-Made of
nucleotides
Bases are UACG, single
stranded, sugar is
Ribose. Copies DNA and
moves into nucleus to
make a protein
• Understand the process of Protein Synthesis (transcription and
translation, where they occur) Terminology: RNA, DNA, Triplet, Codon,
anti-codon, ribosome, mRNA, tRNA, amino acids, proteins
Transcription is the process by which RNA is made from DNA. It occurs in the nucleus.
Translation occurs in the cytoplasm, specifically on the ribosomes. The mRNA made in the nucleus travels out to the
ribosome to carry the "message" of the DNA. Here at the ribosome, that massage will be translated into an amino acid
sequence.
Reading the DNA triplet:
Transcribing it into mRNA
Translating it into tRNA
Translating it into
Amino Acid Sequence
TAC TTA CTC CGG CTA GTT AGT
AUG AAU GAG GCC GAU CAA UCA
UAC UUA CUC CGG CUA GUU AGU
met asn glu ala asp
gin ser
Understand and describe the basic steps in the process of DNA replication.
• Cells in our body are dividing all the time. For example, cell division in the
lining of your mouth provides the replacements for the cells that come off
whenever you chew food. Before a cell can divide, the cell must make a
copy of all the DNA in each chromosome; this process is called DNA
replication.
• In Replication one strand serves as the template for the second strand.
DNA replication is initiated at a region on a chromosome called an origin
of replication. Enzymes called DNA Helicase binds to the origin and
unwinds the DNA in both directions from the origin. As the DNA is
unwound, another enzyme DNA polymerase, then binds and begins to
synthesize the DNA complementary to the original parental strand.
Confidently demonstrate you understanding as to where and how humans
reproduce forming a zygote from gametes (use terms haploid, diploid,
fusion, fertilisation, gonads, testes, ovaries, meiosis and mitosis)
CELL DIVISION understand the difference between the two types and why they occur.
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1. Mitosis- most of the time when people refer to “cell division,” they mean mitosis, the process of making new body cells,
identical to the original parent cell. Mitosis is a fundamental process for life. During mitosis, a cell duplicates all of its contents,
including its chromosomes, and splits to form two identical daughter cells. Because this process is so critical, the steps (or
stages) of mitosis are carefully controlled by a number of genes. When mitosis is not regulated correctly, health problems such
as cancer can result.
2. Meiosis is the type of cell division that creates egg and sperm cells and it is very different to normal cell division. Meiosis
occurs in the testes and ovaries and it produces eggs and sperm for making babies! Meiosis ensures that humans have the same
number of chromosomes in each generation. It is a two-step process that reduces the chromosome number by half—from 46 to
23—to form sperm and egg cells. When the sperm and egg cells unite at conception, each contributes 23 chromosomes so the
resulting embryo will have the usual 46. Meiosis also allows genetic variation through a process of DNA shuffling while the cells
are dividing.
• Karyotyping.
What is is?
Why is it done?
Karyotyping: During mitosis, the 23 pairs of human chromosomes _________- and are
visible with a light microscope. A karyotype analysis usually involves blocking cells in
mitosis and staining the condensed chromosomes with dye. The dye stains regions of
chromosomes that are rich in the base pairs ________ (A) & ________ (T) producing a dark
band. A common misconception is that bands represent single genes, but in fact the
thinnest bands contain over a million ______ pairs and potentially hundreds of
_______.The analysis involves comparing chromosomes for their length, the placement of
_______ (areas where the two chromatids are joined), and the location and sizes of
bands.
Inheritance
Be able to label the parts of the chromosome Chromatid arm,
centromere sister chromatids.
How many pairs of chromosomes are found in human cells?
46 chromosomes in total and 22 autosomes and 1 pair of sex
chromosomes
Autosomes and sex chromosomes.
How is sex of individual determined?
Homologous pairs of chromosomes and non-homologous
chromosomes
• Allele-different form of a gene
(eg alleles for eye colour B-Brown and b-non-Brown).
• Loci- the location of the gene on a chromosome.
• Trait-a characteristic in an individual
• Genes-a section of DNA that codes for a characteristic
• Homozygous- Identical alleles in genotype
• Heterozygous- non-identical alleles in genotype
• Carrier- individual who carries a gene for a
trait but its not found in their phenotype
Describe the difference between phenotype and genotype
and include an example in your answer. Explain dominant
and recessive inheritance.
• Genotype- combination of genes carried in the DNA. Types
of genotypes homozygous and heterozygous.
• Dominant allele- the allele that when present is expressed
in the phenotype or appearance of the individual
• Recessive allele- allele that is masked by the dominant
allele & is only expressed if both alleles are recessive.
• Phenotype- Physical appearance of individual
Explain the differences between Complete Dominance
Complete Dominance and Incomplete Dominance.
1. Complete Dominance in the
heterozygous state one allele
fully masks the presence of
the other alleles
Types of InheritanceUsing the example of Flower Colour
Red Flower allele
White Flowers allele
2. Intermediate Inheritance or
Incomplete Dominance in the
heterozygous state there is a
blending of the characteristics.
3. Co-dominance In the
heterozygous state both alleles
are fully expressed in the
phenotype
Given information about a trait be able to produce a punnett
square that shows the possible offspring of the parents.
Be able to show the Genotypic ratio and Phenotypic Ratio.
Punnett Squares: Many times the predicted results of a particular
cross are examined using a so called Punnett square, after their
inventor. The gametes from one parent are put along the top of
the square, and the gametes of the other parent are put along the
side. Remember! each gamete gets on gene from each gene pair
but not both.